A few years ago, I spent Christmas with the family of my then-girlfriend, Kaz.  She and I had only been dating for a few months, so I was a little nervous at the prospect of being holed up with her folks at what can be quite a tense time, but I must say that her parents went out of their way to be welcoming and seemed genuinely pleased to have me stay.  I guess I was, though, in their eyes, the perfect boyfriend for their darling daughter: a traditional boy-next-door type; conventional, inoffensive and respectable.  Or that's how I seemed.

It's a good thing they didn't find out about what happened between Michael and I.  They might not have been quite so eager to have me sharing their Christmas pudding if they'd known what I'd been getting up to with their son after lights out.

Knowing (while, of course, pretending not to know) that the guy staying in your house is screwing your daughter at Uni is one thing.  Turning a blind eye to the fact he's also buggering your son when the opportunity arises is quite another.

But maybe I'm presenting myself in too dim a light here.  Michael was, after all, a more than willing conspirator.

It started one evening a couple of days before Christmas Eve, after I'd been out for a meal with Kaz, her parents and Michael, along with her uncle and aunt.

It had been quite a pleasant evening, though perhaps a little too formal for my tastes, and we'd eaten in a very salubrious restaurant.  I'd been warned beforehand by Kaz to pack a decent suit with me, and it had turned out that this was what it was for.

The conversation had flowed steadily during the meal and Kaz's uncle and aunt had been just as welcoming and apparently interested in me as Kaz's parents had.  Ironically, my only source of irritation was Kaz.  Every time I looked at her she seemed to be nodding and grinning encouragingly at me.  At first it was kind of comforting to know that she wanted things to go well, but after a while I started to feel uncomfortable.  She'd whisper over at me, "You're doing great, Seb," and I'd feel like I was being monitored; as if I had a history of being disruptive in polite company or something.  I'd mutter, "Yeah, alright Kaz..." and feel my face flushing slightly while the others glanced over at us.

But I suppose Kaz was feeling nervous about the evening and wanting everything to go well.  Her aunt had, she said, a strong influence over her dad, and so if opinions went the wrong way during the meal it would almost certainly make things more difficult between us afterward.

Everything did go well, though, as it happened.

Especially afterward.

I'd been sharing a room with Kaz's brother Michael for a couple of nights before the evening of the meal.  He was a year or so younger than her, eighteen or nineteen, and had just finished his first term at Sheffield University.  The two of us didn't have a lot in common – he was a very quiet and insular guy, as though he hadn't quite fully emerged from a moody adolescence – but we made pleasant small-talk and got along fine at a superficial level.

Kaz's mum had originally offered me the spare room for a couple of nights until her parents arrived on Christmas Eve, but I'd suggested that it would be a lot easier if I slept in Michael's room throughout my stay to make it less of a nuisance changing sheets and moving my stuff.  Kaz's mum had smiled appreciatively.

I felt a little odd at first to be crowding in on Michael's space – his room was almost over-flowing with his stuff and the walls were plastered with posters of bands like Radiohead and Placebo from his sixth-form days – but Michael didn't seem to mind, so the matter was quickly settled.

A fold-out camp-bed was moved from the garage up to his room.

I noticed within those first couple of days that Michael had a few annoying habits, like the fact the floor in his room was always covered with his discarded socks and underwear and the way he masturbated in his bed while I was trying to get to sleep, but otherwise sharing with him wasn't a big deal.

The main advantage in staying with him was that his room was next door to Kaz's.  Michael clearly realised this as soon as I put my bags in his room – he'd muttered something about his room being positioned "convenient distance from the local attractions" and thrown me a sideways smirk – but Kaz, typically, wasn't so astute.

She'd said, that first evening, "You should have taken the spare room... why d'you want to share with that little tosser?"

I'd smiled.  "Why d'you think?"

Then she'd surprised me.  "I dunno... maybe you want to get a closer look at Michael...?"

My smile shrivelled and died.  "What?"

"I dunno how guys' minds work.  Maybe you want to compare us or something..."

I was speechless.

She went on, "You once said that if I was a guy I'd have bigger balls than you..."

"That was a joke," I stated coldly.

"Well why would you be so eager to sleep in his room... you tell me..."

I must say I felt really angry with her right then; I was almost regretting having come to stay with her.

I spoke slowly, my voice betraying my anger, "I suggested I stay with your brother because his room is next to yours... the spare room is down the corridor next to the door of your parents' room... you do the math..."

She went a little pink.  "Oh."

Then, grabbed my hand.  "Look, sorry, Seb.  I just... well, that's the kind of stuff Tom used to say... just to wind me up..."

I muttered,  "I don't want to discuss your ex-boyfriends, Kaz.  Not now."

"I'm not discussing him.  It’s just that he'd say stuff like that.  Say I had a guys' arse..."

"You haven't"

"I know.  But he knew it pissed me off... and... sorry... I just still expect it..."

We agreed to forget about it but what she'd said got me thinking.

In the middle of the night, after I'd returned to Michael's room from having a little fun in Kaz's, I took a couple of minutes to look at him while he slept.  He was facing away from me with the duvet pushed to the front of him.  In the dim light from the window I could see the sweeping curve of his back, his arse cheeks looking full and round inside his briefs and the hairless backs of his thighs.

Kas had been right: the two of them did have very similar bodies, at least from behind.

Maybe she did have a guys' arse.

I found the similarities intriguing but not erotically so.  Perhaps I would have been a lot more interested in studying Michael's body if my cock had not just spent itself in the body of his sister, but right then I felt exhausted and wanted to try and get a bit of sleep before the alarm went off.

The next morning served to heighten my curiosity.

By the time I awoke, Michael had already showered and was drying himself in the middle of the bedroom.

I sat up in bed and watched him as he roughly towelled his hair dry.  His body was remarkably similar to Kaz's, although his muscles were more pronounced and his joints were more angular.  His complexion was identical – his skin pale and smooth and hairless except for around his crotch – and his limbs were similarly proportioned.

He finished drying himself and threw the towel onto his bed.

Standing unashamedly naked in front of me, he put his hands on his hips and said, "Morning, Seb."

I smiled.  "Hi Michael."

He grinned.  "Busy night?"

I guessed I must look like hell.

I shrugged.  "Kind of.  I didn't disturb you, did I?"

He shook his head.  "No – I didn't hear a thing.  I... er... didn't disturb you, did I?"

I must have looked puzzled because he threw a quick glance down to his crotch.

I realised he was referring to the activities of his right hand after we'd turned the light off.

I chuckled, concealing my surprise that such a quiet and apparently shy guy would be so comfortable about mentioning masturbation.  I said, "No worries, mate.  If your sister wasn't keeping me so occupied, I'd be joining in..."

He laughed and walked over to take a pair of briefs out from his drawers.

He muttered, "Feel free..." which struck me as slightly odd, but not too far from the ordinary.

While he pulled his briefs up – a light grey pair – I got a better look at his crotch.  Just taking a polite interest, you know.

His cock was pretty average, maybe three or four inches long, but his balls were quite amazing.  They were like two billiard balls straining as though ripe and swollen inside his tight scrotum.  His cock looked insignificant in comparison, as it lay over the top of his sack with one, large pink ball on either side of it.

It looked like my joke to Kaz, the one she'd reminded me of, had been far more astute than I'd realised.

Michael tucked himself into his briefs and his balls made two large bulges in the front of them.

I figured it was time to get up.

I heaved myself up from the camp-bed and pulled off my own briefs, a tight-fitting white pair.  They tore a little at the tip of my cock, where semen from my visit to Kaz the previous night had dribbled out during the night and dried.

"Time to hit the shower, I guess..." I muttered to Michael.

I glanced at him and saw that he was checking out my cock, just as I had his.  I wasn't surprised or embarrassed: in my experience of being naked around other guys, it's a pretty normal for them to compare each others' kits.

And, in any case, he was probably wanting to see what his big sister was getting served up.

I bent to pick up my towel and noticed him check out my backside too.  Not quite so normal, but still in no way odd.

I turned back to face him.  He glanced at my crotch again and was no doubt mentally comparing his hefty balls with my own.  Although I've always thought of my balls as being quite a comfortable size – about as big as a pair of walnuts – they looked pitifully unsubstantial up against his. 

I looked down at myself and then back at the front of his briefs.  It was pretty clear that, even if my balls weren't any competition for his, I was the out-and-out winner in terms of cock size.  Mine was five or six inches long, even though it was limp, and as thick as a carrot.  His looked like an earthworm in comparison.

He said, "The shower's pretty straightforward.  The outer dial controls pressure and the inner dial controls temperature."

I nodded.  "Sounds okay..."

"I just thought I'd tell you because the writing's worn off the dials."

"Cheers."

Then he turned and bent over to get a pair of socks out from the drawers beneath his bed.

I'm sure it was unintentional, but the way he stuck his arse out towards me really took my breath away.  His legs were wide and his knees were slightly bent; his back was bowed and his arse was thrust towards me with the cheeks splayed open inside his briefs.

I think I might have gasped.

You see, that's the pose that his sister is very adept at assuming when I fuck her from behind.  The exact same pose being expressed by her brother.

I was unable to stop myself from mentally picturing myself fucking him.  Walking up behind him, pulling down his grey briefs just like I did with his sister's white panties, and driving my cock into him.  Pushing myself into his arsehole just as I would penetrate his sister's pussy.  Relishing the pungent odour of his anus as I entered him just as I would the sharp scent from Kaz's vagina.

I wondered if he would whimper and cry out like Kaz did when I fucked her.  Whether he would want me to reach round his chest and play with his nipples like his sister did.

Before I knew it my cock was rising to life, almost poking into the back of his briefs as it lengthened and thickened in front of me.

Michael stood up and turned back toward me.  I quickly came to my senses.

He glanced at my cock, now almost fully hard, as I struggled to wrap a towel around it and my waist.

He smiled and I felt myself turn scarlet.

I grabbed my shampoo and hurried out from the room.

I couldn't make my erection subside while I showered.  No matter how I tried to redirect my thoughts, the image of Michael bending over and thrusting his arse towards me kept returning to my mind.  My erection would pulse upward with even greater vigour.

In the end, I gave in to its insistence and roughly wanked myself beneath the spray of the water.

I was trying to visualise myself fucking Kaz from behind, but my imagination would keep overtaking me.  Without warning she would metamorphose into him.  I'd find my cock sliding in and out of his tight, pink arsehole.  My balls thumping against his larger, rounder ones.  My fingers on his flat chest, teasing his erect nipples.  His voice, not hers, urging me to continue.

I fought to reject the mental picture of him for a while and then gave in; accepted that it was him that I wanted to fantasize about and put it down to "healthy sexual intrigue about a girlfriend's sibling".  I was sure I'd read about something like this in a textbook.  It was perfectly normal; not an authentic gay desire at all.

I quickly finished masturbating with the thought of him reaching his orgasm while my cock drove in and out of his splayed buttocks bringing me to completion.

I was careful to wash the splashes of my semen from the wall of the shower cubicle.

Nothing else of any significance happened between Michael and I until after the meal with the uncle and aunt.  There were a couple of knowing glances across the breakfast table after I'd finished showering and dressing, and a repeat of the fairly obvious crotch comparisons over the following couple of mornings, but nothing major.

The main event – and, as it happened, the start of an stimulating friendship between Michael and I – began when we'd got back from the restaurant.

I'd noticed that Michael had been drinking far more than a guy of eighteen ought to, even one who has just experienced his first term's drunken revelry at University.

The fault could mainly be lain at the door of his uncle: he'd been going on about how he hadn't had a "legal drink" with his nephew yet and that this is what he'd been waiting for since Michael's christening.  So he kept getting extra drinks for Michael despite Michael's mum's disapproving glares, plying the lad with pints of lager followed, as often as he could get away with, by whiskey chasers.

I suppose the uncle probably just wanted to loosen Michael up a bit: Michael was clearly uncomfortable about socialising like this and spent a lot of the time in contemplative silence.

I could see what the uncle was trying to do, but it didn't seem to work.

The alcohol just made Michael sullen.  He'd glance over at me and seem to resent the fact that I was having a reasonable time, enjoying the company and chatting freely.  Or maybe he was annoyed that no-one was talking to him.

It only became clear that Michael had had way, way too much to drink when we got up to leave the restaurant.  The poor guy could hardly walk; he veered around the restaurant, almost colliding with other diners, and had to use the backs of peoples' chairs as support.

Kaz's father and I helped him back to the car, while Michael insisted loudly that nothing was wrong.

We had to pull into a layby on the A65 for Michael to be stumble out and be sick.  I went with him; the rest of the family pointed out that I was a trainee medic and so it would be "good practice".

While he threw up, I put my hand on his back to let him know I was there.  His skin felt hot through the material of his shirt and jacket.

He muttered, between surges, "I'm really sorry about this, Seb.  I didn't want you to see this..."

I said, "Don't worry about it.  I've seen a lot worse..."

When we got back to the house, Kaz's mum told her dad to sort Michael out and put him to bed.  Her dad looked queasy.

It was Kaz who suggested that I "might like to do the honours".  I think she had meant it as a joke.

But her mum looked at me brightly and said, "Ooh, would you, love?  It'd be ever so good of you..."

I couldn't really say no.

I went to the stairs and found Michael splayed out halfway up.

I said, "Come on then, mate.  Let's get you up to bed..." and helped him to get up the rest of the stairs.  I think I noticed that, as Michael used me for support, he kept touching my thighs and would sometimes brush his hand against my crotch, but I never thought much of it.  The lad was paralytically drunk; he didn't know what he was doing.  Or so I thought.

I got him into the bathroom.

"Do you want to be sick again?"

He drawled, his voice husky and the words merged into one sound, "No that's passed."

"Well you better wash out your mouth and brush your teeth.  The acid from your stomach will burn the enamel off them in your sleep..."

He raised his eyebrows in surprise and then tried to focus on his toothbrush.

I did most of it for him.  Passed him a glass of water and watched him rinse his mouth, put paste on his brush and watched while he clumsily poked it around his teeth, and then refilled the glass for him to rinse again.

Then I told him to drink a couple of glasses of water to ease the hangover he'd be feeling the next day.

I joked, while he drank the water, "If you end up being my brother-in-law, you're never gonna live this down, mate..."

He smiled.  "You'll have to remind me, then.  I never remember anything when I get like this..."

His words sounded a lot more coherent.

I got him to his bedroom and told him to undress.

He theatrically collapsed onto the bed, lying flat on his back.

He giggled.  "I can't.  Will you help me?"

I smiled.  "Of course I fucking won't."

"I'll sleep like this, then."

I shook my head.  "You can't sleep in your suit.  What if you throw up again on it?"

"I'm not gonna throw up.  I told you."

"Well you'll crease it to hell.  Your mother will be pissed off with you..."

He giggled again.  "She asked you to look after me.  So she won't be pissed off with me, will she?"

I sighed.  "Okay then.  But I'll definitely remind you about this.  Probably in the groom's speech on my wedding day..."

He laughed.  "Yeah... you're on..."

He pulled himself up from the bed a little as I took off his jacket.  He had his eyes closed but was smiling.

I undid his tie and pulled it off and then loosened the top few buttons of his shirt.  His smooth hairless chest was underneath.

Then I went down and undid his shoelaces, removing his shoes with some difficulty.  His socks were hot and wet beneath them.

I said, "I'm not touching them... you'll have to sleep in your socks tonight..."

I went back up to face him.

"I think you can take your own trousers off," I suggested.

He chuckled.  "Naah... I'm too pissed, mate.  You'll have to do it..."

"You're not serious..."

He giggled again.  "I am..."

I said, "If you lose your dick in a bizarre zipper accident, it's not my fault..."

He laughed but made no effort to take his own trousers off.

So I bent over him and undid the belt.  As I did that, I felt something hard beneath the material of his trousers.  I thought, "It can't be his cock..."

But it was.

After I'd unbuttoned and unzipped him, I went down to the foot end of his bed to pull his trousers off.  As they came down his legs they revealed a pair of black briefs sporting the unmistakable tent of a captive erection.

Michael chuckled.

I said, "I guess you like being undressed..."

He smiled and looked up at me.  "No more than you enjoyed undressing me, I bet..."

I guess I just shrugged at him, puzzled.

He went on, "I bet you're as stiff as I am..."

I laughed.  "Funnily enough, undressing my girlfriend's brother doesn't do much for me..."

He smiled mischievously.  "Show me then..."

I laughed again.  "I'm not showing you my dick, mate..."

"Because you're hard...!"

"No!  Because you're a guy and it would be weird..."

He chuckled at that.  "It would be weird if you were hard... but since you say you're not, you've nothing to lose by showing me..."

I laughed again.  "Nice try, Michael, but no way."

I walked towards the door.

Now he said, "If you get your dick out, I'll suck it."

I stopped.  My amusement evaporated instantly.

"What?"

He smiled over at me, "I said, if you get your dick out, I'll suck it for you..."

I spoke slowly.  "Come on, Michael.  You know I'm not gonna do that..."

He poked his fingers in the sides of his briefs and yanked them down, exposing his six inch erection and those huge balls of his.

He said, "Okay, so why don't you suck mine?"

I closed the bedroom door quietly and walked back over to him.

I shrugged.  "Because – even if I wanted to – it wouldn't be right..."

"Why not?"

"You know why not."

He shrugged.  "Come on, don't worry, Seb.  I remember nothing in the morning when I get like this..."

"You don't sound too pissed anymore..."

He grabbed his cock and pulled back his foreskin to expose its round pink head.  It looked wet.  "Come on, Seb.  Suck it... I really want you to..."

"Come on, Michael.  You're Kaz's brother..."

"What difference does it make?"

I chuckled humourlessly.  "Well, you're a guy for a start..."

He nodded.  "Yeah... and that makes it more interesting... I mean, d'you think I taste the same as she does...?"

I shook my head.  "I'm not going to be able to imagine I'm with her, if that's what you mean... the big pair of nuts between your legs will make that kind of difficult..."

He laughed again.  "I didn't mean that.  I just meant it'd be interesting for you to see how different we are... what we're like... what we like to do..."

I shook my head.

He smiled.  "Okay.  Never mind.  I'll just have a wank while you go downstairs and tell them you've tucked me in..."

He pulled his shirt off and threw it on the floor, then lay back and closed his eyes.  His hand started up a moderate rhythm on his cock, sweeping his foreskin up and down his shaft and making a wet clicking sound.

Then he opened his legs and his other hand went between them.  It looked like he was rubbing the ridge between his balls and his arsehole.

I'd been going to go downstairs – truly I was – but seeing him do that stopped me in my tracks.  It was the same motion that Kaz often does while she's in a similar state of pleasure; she just sort of tickles that ridge with the tips of her fingers.

Now Michael was showing me his own version.

I walked to the foot of the bed so that I could get a better view of what he was doing.

Michael pretended he was oblivious to my presence, but opened his legs wider to let me see right down to his arsehole.

I saw that his way of stimulating himself was more elaborate than his sister's.  He had developed it to better suit his male anatomy.  His fingers caressed those large balls of his, sweeping along their midridge and tickling the base of his cock.  Then they swept back between his thighs and played around his arsehole, teasing the puckered entrance gently and occasionally venturing the tip of a finger into it.

Kaz never did this; perhaps it's only males who find this an erogenous area.

By now I was captivated.  My cock throbbed inside my briefs and I felt my breath becoming faster.

I had to go through with this; I'd be more likely to regret it if I didn't than if I did.

Perhaps Michael was being truthful when he claimed he wouldn't remember this in the morning.  Perhaps not.  By now it didn't matter: all that mattered was that I wanted to see what pleasured him; to find out how my girlfriend's younger brother compared to her.

I hurriedly took my jacket off and threw it onto the camp-bed.  Then I undid the top button of my shirt and loosened my tie.

I said, "If you hear any noise outside – any of the stairs creaking – you get under the duvet and I'll pretend I'm folding your clothes, okay?"

He nodded and I walked over to him and knelt by his bed.

I could smell his genitals.  The scent was stronger than Kaz's but bore some similarities; the male equivalent.

He repeated, "Suck me, Seb..." and I let him pull my head onto his cock.

He pumped it eagerly into my mouth, losing control like his sister sometimes did, and I felt his precum oozing onto my tongue from the engorged head.

I let him hold my head firmly and to fuck my mouth with rapid, insistent strokes.  His balls thumped against my nose, the hairs tickling me with each thrust, and the thick heavy odour of his genital sweat filled my nostrils.

I let him continue sliding his cock in and out of me until he began panting in pleasure.

Fearing he might be about to climax, I pulled away and told him to kneel in front of me on the mattress.

"I'll kneel on the floor," I gasped, "You kneel in front of me.  Take your briefs off."

He got up and did as I asked.

"Like this?"

I nodded.  "But open your legs further..."

He knelt on the bed, legs wide open, naked except for his socks.  His cock curved upwards from his large balls, looking wet and throbbing gently.

I leaned forwards and began sucking him again.  He grabbed my head as he had before and started fucking my mouth.

Now his balls whacked against my chin and his pubic bush tickled my nose.

I reached between his legs and worked a finger into his arsehole.  He gasped in appreciation and pushed his backside towards my hand.

His rhythm quickly changed: he began thrusting his arse onto my hand rather than his cock into my mouth.  Like his sister. who prefered vaginal rather than clitoral stimulation, Michael seemed to prefer being penetrated than to having his cock sucked.

I pulled my mouth away from his cock, arching upright stiff and slick, and concentrated my efforts on his arse.  I licked his balls while I finger-fucked him, tasting the sweat on them and feeling how large they felt inside his scrotum, and then I worked my mouth between his legs and long the hairy ridge.

Now I withdrew my finger and, as Michael opened his legs as far as he could, pushed my face right into his arse cleft.  My tongue found his hole and slid in easily.

He grunted something like, "Oh fuck!  Yeah!" and I tongued his rectum as deeply as I could manage.  His arse tasted strong and rough, but I found that my cock was almost bursting from my trousers at the pleasure I was getting from being so intimate with him.

I'd never even done this to his sister!

I pulled away from him and, both of us gasping, said to his disappointed face, "I need to fuck you."

His eyes widened with surprise.

He muttered, "Yeah... yeah..."

I grabbed my wallet from my trousers and pulled out a condom.  I unzipped my fly, disentangled my throbbing cock from my briefs with some difficulty, and then rolled the condom quickly down its length.

I said, "On your back.  Legs up."

He moved to lie along the length of the mattress, his head on the pillow, but I stopped him.  "Not like that.  Your arse on the edge of the mattress, so I can fuck you from here."

He struggled to get into the right position and chuckled, "You've done this before..."

"Yeah.  Your sister's pretty good at it..."

He got into position, holding his legs up near his shoulders and opening his arse as wide as it would go.  I could tell from the size of his dilated hole that this would not be the first time he'd ever been fucked.

He'd clearly been having a little fun in Sheffield.

He said, "Will it work?  I mean, my arse is a bit different to... er... what Kaz has got..."

I liked the way he couldn't bring himself to give a name to his sister's genitals.  Even though he had quite easily brought himself to seduce her boyfriend.

I smiled.  "Like you said, Michael.  The fun will be in the finding out..."

With that I plunged my cock into him.  My saliva had lubricated him nicely and I slid in quite effortlessly.

He gasped, "That feels so good."

I threw him a smirk.  "That's what she always says..."
 

He smiled back.

I grabbed his legs and held them as I began fucking him gently.  He groaned in appreciation.

His hand went to his cock and he began masturbating himself to the same rhythm as I was fucking him.  His large balls bobbed around like a pair of ripened apples on a tree.

We were soon both panting and sweating.

I briefly paused once to pull my balls out from my fly.  "They're trapped in the zip... they might not as big as yours, mate, but it's still painful..."

Now they hung over the front of my trousers, slapping against Michael's buttocks as I fucked his arse.

I must have fucked him for about five minutes before he came.  I think he'd have lasted longer – I was deliberately controlling my rhythm whenever he looked like he was close – but for the fact that I started teasing his nipples between my finger and thumb.

He shot what seemed like a gallon of semen.  Big balls produce big loads, apparently.

I quickly finished myself off inside his arse and then, with the condom pulled off, over his crotch, and added my own drizzle to the puddle on his stomach.

Almost as soon as he'd climaxed, I heard his mum shouting up the stairs, "Are you alright, Sebastian?"

I called back, trying to keep my voice steady despite being so out of breath.  "Yeah... I've just sorted him out... I'll be down in a sec..."

She called up, "Do you need a bucket for him?"

I looked down at the pool of cum on his stomach and Michael smiled up at me.

"Er... no... I don't think so..."

She called up, "Okay.  Well hurry down... I've got some of Katherine's baby pictures to show you..."

Michael grinned.  "Ooh lovely..."

Before I left the room to return to them, Michael said, "We'll do this again, yeah?"

I nodded.  "Yeah.  If you like."

"Yeah."

And then, as I was closing the door, "I bet I can suck your cock better than Kaz can..."

I smiled and whispered back into the room,  "Well there's only one way to find out..."

He chuckled and I closed the door.

The rest of my visit was difficult: I found myself performing a kind of balancing act between Kaz and Michael while trying not to arouse any suspicion.

I wasn't sure which of them I preferred.

Kaz was great fun to be with, she understood me well and I'd grown to love her enormously in just the three or four months we'd be seeing each other.

But Michael... well, Michael could fuck like a rabbit and suck cock like a pro.  And there's a lot to be said for that too.

I met him on and off throughout the time I dated Kaz.  Once we went on a camping holiday – Kaz and I, with Michael and a mate – and I found, again, that Michael and I were getting together every opportunity we had.

The more I got to know about Kaz's body, the more questions it posed about Michael's and, whenever the two of us guys met up, I just had to have them answered.

I'd say something like, "She's really moody at different times of the month.  I know you don't get a period, but do you get like that?"

And he'd think about it and reply, "Well maybe it's because she's got big ovaries or something.  They're producing more hormones, maybe.  I mean, I've got big balls so it'd stand to reason that she'd have big ovaries..."

And I'd nod.  "Yeah.  I guess..."

It became a developing fascination of mine to find out how some of Kaz's sexual preferences and foibles would be expressed in a male.  Most of what Kaz enjoyed having done to her vagina, Michael found very gratifying when applied to his arse.  Apart from that, his erogenous areas seemed to match hers and his preferred positions were clearly the male equivalents of hers.

One of the things that saddened me most about the break up of my relationship with Kaz was that I never got to see Michael again.  I guess he took her side in the argument we had; he's her brother so you can't really blame him, can you?

I find myself wishing sometimes that my wife Melissa had a brother.

It would be interesting to get to know him.

Those of you who have read some of my other stories will know how much I enjoy having sex with my brother and finding out how, although we are so similar in many respects, some traits are expressed very differently in each of us.  The theme of this story is very similar, with Michael offering me a chance to experience a male version of my then-girlfriend's body and sexual tastes.

The story is predominantly true, although the first time Michael and I actually got together was in an extremely confined tent rather than in his bedroom.