In the morning I lie on, reluctant to get up. Saturdays should mean morning sex, lazy breakfasts and afternoon pints, but with Heather away with work, there’s not much to get up for. Eventually, I hear Heather’s sister, Katie clattering around the kitchen and I crawl out of bed, pull on a tee shirt and jogging bottoms and wander out to say hello. She’s reaching up to get a jar of maple syrup from the top shelf and I’m treated to the sight of her tee-shirt rising up and flashing a glimpse of white knickers with multicoloured polka dots on them which reminds me of a version of twister. She turns and catches me looking and we both blush with embarrassment.

“I’m just making breakfast. Have a seat, they’ll just be two minutes.”

I sit and watch as she pours the coffee and soon we are both tucking into pancakes with maple syrup.

“What’s up?”

I look up at her. She’s got a concerned look on her face.

“What do you mean,” I try to bluff. “There’s nothing up.”

“Look, Mark. Don’t the idiot. I can tell you’re not happy. And it’s not just because Heather is away for a few days.”

I shrug, but when I see the same expression that Heather pulls on Katie’s face, I know I’m in for an interrogation so I decide to unload. I expect Katie to laugh and brush aside my suspicions when I suggest she might be sleeping with her boss so I feel a bit shocked when she just sits there and looks at me.

“I think you need to get out more. You can’t sit at home moping about Heather. Let’s go out tonight.”

I start to shake my head but she won’t take ‘no’ for an answer and eventually I agree.

A quick spray of deodorant under the armpits and a clean tee-shirt and I’m ready to go but Katie seems to take forever to get ready. Finally, she shouts from her bedroom that the taxi is on its way. I knock back the rest of my bottle of beer just as Katie comes out of her room.

She looks stunning. Her blonde hair is hanging loose around her shoulders and she looks so good in a cropped top and skater skirt. The thigh highs and heels just set the outfit off.

I make another tit of myself by uttering, “Wow, you look gorgeous,” when I see her to which she retorts that I must mean she looks terrible the rest of the time. When I try and apologise she giggles and tells me she’s only joking and she takes my hand and leads me out of the flat and downstairs to where the taxi is waiting.

The alcohol I’ve already drunk has lowered my inhibitions and loosened my tongue which is never a good combination. So when we are standing in the bar of the club, vodka and coke in hand and Katie mentions Heather, I raise my hand and tell her that I love Heather and I was just being silly and for her to forget everything I might have told her earlier. But Katie just laughs and strokes my arm.

“But Mark, Heather has cheated on every bloke she’s ever been with. You must have known she wouldn’t stick with you?”

“What do you mean? she’s only been with two boyfriends before me.”

Katie howls with laughter then suddenly stops, her eyes wide.

“Fuck? Really? That’s what she told you?”

“Yeah. A guy she went out with through the last two years of school that dumped her as soon as she completed her A levels and then one guy at university which had been an on, off and on again relationship until she met me.”

“Oh, Mark. I think Heather has been sanitising her past.” Katie pauses while she takes a sip of rum and coke. “I bet she didn’t tell you about our mum’s best friend walking in on her, naked at a party and covered in strawberry yoghurt with a guy licking it off her tits?”

I swallow. “No, but that was probably the boy she told me about.”

“Tell me, Mark. Was Heather good in bed that first night?”

I nod.

“How do you think she got that good, Mark? My sister is a slut.”

Katie steps closer as if she doesn’t want anyone else to hear as she describes Heather having three boys on the go at the same time whilst in her first year at university. How she’d told Katie about one time that she’d brought a random guy home and fucked him and he’d only just left her room in the halls of residence when her boyfriend turned up and she fucked him too.

I can feel Katie’s breath on my neck and smell her perfume in my nose and despite myself, I can feel my cock growing hard as Katie tells me all about a past I knew nothing about.

I can feel Katie’s breast press against my arm. Her nipple is hard and when I move my arm slightly, instead of moving away she presses in more. Her hip presses against my crotch and I swear I can feel her smile even though I can’t see her face when she feels how hard I am.

“It’s about 2 am in Germany,” she whispers. “Do you honestly think Heather is asleep or has she got Hans running his hands over her?”

She giggles at her bad German accent then bites her bottom lip as she gazes into my eyes, waiting for a reaction. I blush and knock back my drink.

“Another?”

“Did she ever tell you she fucked my boyfriend once? No? I doubt she did. I’d missed the bus home from school. He’d called round to our house. She was home from uni. She invited him in to wait and by the time I’d walked home, he was balls deep in her, fucking in her room with the door open for me to catch them at it.”

“I meant another drink, not another story.”

“I bet she pretends to be Miss Goody Two Shoes for you. I bet she hasn’t even let you fuck her up the arse.”

She glances left and right.

“Has she ever fucked you in a club toilet? Has she ever begged you to fuck her harder as you slam it into her, her face pressed against the cubicle door, knowing there are people listening outside?”

I stare at her, not daring to open my mouth, unsure what would come out.

“I can tell she hasn’t. Oh, Mark, Heather’s my sister and I love her dearly but she’s a right dirty little slut too.”

Her fingers slide over my chest as she whispers in my ear.

“I reckon she’s lost count of the number of boys she’s slept with. If I’m honest, I’m surprised you guys have lasted this long.”

The alcohol flowing through my system has obliterated any defences and as I gaze into Katie’s eyes, she tilts her head and kisses me. Her lips are so soft and I can taste her cherry lipgloss mixed with the rum and coke as her tongue traces the edge of my teeth.

“Katie,” I plead. “We shouldn’t.”

“You think Heather is saying that in her hotel room in Germany?”

She grinds against me, I know she can feel how hard she has made my cock as she rubs herself against me. Her arms wrap around my neck and her breasts press against my chest.

“Have you ever fucked Heather in public?” Her whisper is like a rush of hot breath in my ear. “We could do it now. I’m not wearing any knickers.”

Fuck, my brain has gone AWOL. My cock is in complete control now and I can only hang on for the ride. She takes my hand and slips it under her skirt. I can feel her heat and slickness on her labia as she guides my fingers along her slit. Despite the crowds around us, it’s like we are in a world of our own.

“I know you want to. I’ve seen you looking at me,” She pauses. “And I want it too.”

She flutters her eyelashes at me. She has the same ‘fuck me’ eyes as Heather. I extend my middle finger and push it between her lips, feeling her wet velvet gripping my finger as I push it inside her. She presses herself closer to me as if willing me to finger her deeper.

My finger curls inside her. She’s so wet, I can feel juices oozing out of her. Suddenly I realise what I’m doing. I pull my hand away.

“We can’t. Not here.”

She looks around, grabs my wrist and drags me to the toilets.

“Katie, this is crazy.”

She pulls me into the Gents and into a thankfully empty cubicle. I never even get to notice if anyone saw us before we are in the stall and she has locked the door. Her hands are at my belt and in seconds she is crouched down on her honkers with her cock in my mouth. I look down and meet her gaze. Fuck, her eyes are staring up at me, looking like the only thought she has in the world is how much she wants my cock. She runs her tongue in circles around the head, slurping it, sucking it, and coating it in her saliva.

I’m grateful for the alcohol in my system for otherwise I reckon I’d have already cum all over her face. She takes it into her mouth. She gets about halfway down the shaft before kissing it and letting it slide out again. I can see the ring of red lipstick marking how much she was able to take.

“You have such a delicious cock, Mark. I need you to fuck me with it.”

She stands, pulls her skirt up and shows me her bald pussy.

‘Fuck me,” she begs. “Fuck me now.”

She pulls on my cock as she leans back against the cubicle wall. Her legs are spread and she slides the head of my cock between her labia. I put my hands on the wall on either side of her head, trying to control my breathing as she smears my cock in her juices.

My hands drop to her ass and I pull her onto me. I press my hips forward and up and my cock slips easily into her. She’s tight but soaked and the heat feels incredible. She lets out a gasp of approval and whispers for me to fuck her harder.

My cock seems to swell inside her. Every nerve ending tingles as I begin to move in and out. She wraps her legs around my waist and gravity pulls her fully down onto my cock. I rock my hips, bouncing her on my cock. It’s fast and dirty and I know it won’t last long. I bend my head and bury my face in her neck as I slam into her. Slapping sounds echos around the cubicle every time her ass slaps against my hips.

Her pussy seems to milk my cock and with one last thrust into her, I unleash spurt after spurt of cum. I sort of collapse on top of her, my forehead pressed against the wall, somehow holding me up. I’m panting until I get my breathing under control. She lowers her legs to the ground and I gently ease out of her.

I blush when she looks at me. The realisation of what we have done begins to sober me up. She sees me wavering and leans in and kisses me again.

“Let’s go home,” she whispers and we quickly leave the cubicle. A group of guys cheer and wolf whistle as we exit and I blush more, realising they’ve heard everything. Katie just grins and calls them perverts and we head out of the club, laughing at what we’ve just done.

After the noise and everything in the club, the taxi feels like a cocoon. We are alone, except for the voyeuristic eyes of the driver watching us in the rear-view mirror. Katie doesn’t care and we kiss the whole trip home. Her fingers roam up under my top or down over my crotch. Her skirt is bunched up and my fingers move from her thigh to her ass and back again as we kiss. In the brief moments that we come up for air, I smile and adore how her pale blue eyes sparkle.

I quickly pay the driver when we get home and follow her inside. There isn’t even any discussion about what happens next. She heads straight to my bedroom and the big king-sized bed, her clothes dropping, discarded on the way. She lies naked on the bed, waiting for me, biting her bottom lip as she watches me struggle to get my jeans off.

I climb onto the bed, crawling up between her legs. The thought that the last time I was in this position was with her sister barely causes a flicker of guilt as I drag my tongue up her leg and taste a dribble of my cum from earlier that has run down her inner thigh.

I’m not sure what time we finally stop but it’s getting light. Insatiable would be the best word to describe her I think as I drift off, my fingers tracing the curve of her hip. She lies draped over me, with her blonde hair fanned out on the pillow.

I wake up to the most glorious sensation. I’d been dreaming Heather was on her knees giving me a blowjob but when my eyelids flutter open, I realise it’s Katie kneeling on the bed, running her tongue along the shaft and swirling it around the tip. She sees I’m awake and giggles and asks if I’m ready for more.

That kind of sets the tone for the rest of the week. Monday morning she kisses me goodbye, telling me she can’t wait for me to get home and she’s wet already. A text arrives at lunchtime. A close up picture of the damp patch on a pair of pale pink knickers with an accompanying message telling me that Katie wants me to take these off with my teeth later. By Thursday night, we’ve fucked everywhere in the apartment; in the shower, over the kitchen counter, on the sofa, over the sofa, on the floor, up against the wall, the front door and the freezer and in every position we can think off on my girlfriend’s bed.

We are lying on the bed, drenched in sweat when Katie looks at me, her eyes downcast.

“What happens tomorrow?”

I’ve been dreading this question. I shrug and take the coward’s way out.

“I dunno. What do you want to happen?”

“Jesus Christ, Mark!”

She throws a pillow at me, climbs off the bed and gathers up her clothes.

“Grow a pair of balls, you fucking arsehole.”

I stand up and reach for her.

“Katie, wait. I didn’t mean it like that.”

She glares at me.

“So you don’t care if I stick around or fuck off. You don’t know whether you want to be with me or my sister?”

My brain is stuck and I can see my arms flailing as I try to think of the right thing to say. Every sentence I think of sounds worse than the one before and I’m reduced to standing with my mouth opening and closing like a goldfish.

“You’re a fucking cunt, Mark.”

~~~

Katie has already left for work by the time I get up. I quickly strip the bed and pile it into the washing machine, realising the last thing Heather needs is to smell the stale odour of a week’s worth of fucking on the sheets when she gets home. I do a quick tidy up of the bedroom, ensuring there are no stray pairs of Katie’s knickers or anything incriminating under the bed and head for work. The thought of what might happen when I get home causes a knot in the pit of my stomach.

I take longer to finish up at work than normal and I’m in no hurry to get home. When I open the door, I can smell Chinese takeaway and walk into the kitchen to see Heather there, alone, serving up two meals.

She runs around the island and hugs me and I wrap my arms around her on autopilot.

“God, I missed you,” she whispers as she buries her face in my shoulder. Finally, she releases her grip and we stare at each other, then kiss.

When we pause for a breath, she smiles and tells me Katie has gone out for the evening so we have the flat to ourselves. She leads me over to the sofa, unbuttoning my shirt as we go, the tie is tossed to one side and by the time she guides me down onto the sofa, my belt is unbuckled and my pants and trousers are around my knees.

“What about dinner?”

“Fuck dinner.”

She straddles me, kissing me as she runs her fingers over my chest, whispering, “I’ve missed you so much,” as she runs her fingers through my chest hair and around my nipples. She kisses my mouth and neck as she grinds against me.

Her hand reaches down and pulls her knickers to one side. She grabs my cock and that is when Mr Floppy decides to make an appearance. I can feel myself softening in front of her. Her eyes show a mixture of confusion and panic as she tries to guide my deflating cock inside her.

I try to think about sex, about fucking her, about her mouth sucking me off, but images of Katie and Heather swirl through my head, fighting for attention.

“I’m sorry,” I stutter. “This has never happened before.”

Heather slides off me, lowering herself down onto her knees as she takes my soft cock in her hand and runs her tongue around the head.

“Maybe I can wake you up,” she whispers before taking my cock into her mouth. She gives me her classic blowjob technique. Tongue flickering against my frenulum as she moves her lips up and down the shaft, sucking it into her mouth. I try to will myself hard but it’s no use. No matter what I think of, no matter how much she sucks and licks my cock, it doesn’t get any bigger or harder.

The hurt in her eyes when she finally admits defeat and stands up makes my heart ache.

“I’m sorry,” I plead. “I’m just tired.”

I stand up and pull my trousers up, following her back towards the Chinese takeaways. She brushes her hair back from her face.

“Yeah, maybe we’re both tired. It’s been a hell of a week. Hopefully, we’ll have more fun at Mum’s birthday tomorrow.”

Shit… her Mum’s birthday…. I’d completely forgotten about it.

“Do you still fancy me?”

Another variation of the same question her sister had asked me last night.

“Of course I do.”

It slips easily from my tongue before I can even evaluate if it’s true or not. I just know that is what she needs to hear. I wrap my arms around her and hold her.

“I’m just tired. It’s never happened before.”

“Maybe it’s because you’re becoming such an old man.”

She grins up at me.

“Excuse me, I haven’t even reached my Jesus year. Enough of the old man.”

She kisses me again.

“Ok, grandad. Come and eat your dinner. I’ll even slice it up nice and small for you.”

Even without the sex, it’s nice having an evening to ourselves. We sit on the sofa and share a bottle of wine while we update each other on the past week. Heather’s trip sounds exhausting and stressful. If she was fucking around, she hides it well.

“So, how’d you and Katie get on?”

I know she and Katie were texting a lot. Katie had even texted a reply one night while I was fucking her doggie style so I’m guessing she wants to hear my side of the story. I play it safe, telling her we watched a bit of tv and a couple of nights out in the pub.

“Have you met her new man yet?”

“What? No. She never mentioned anything.”

“Well, it’s early days and god knows what he’s like, but knowing Katie there’s no doubt he’ll be unsuitable. She just said she’d met a new bloke, that I’d really like him and the sex is amazing.”

“Is that where she is tonight?”

“Must be. She just sent me a text saying she wouldn’t be in this evening but could she still get a life down tomorrow. So I’m sure we’ll find out all about him tomorrow.”

We sit in silence watching Friday night chat shows while my brain runs around the block in a panic. Fuck, what the hell is Katie up to? The thought of spending a two-hour car journey with Heather and Katie fills me with dread. Not to mention dealing with a party and staying overnight. I wonder if it’s too late to ask Katie to move out now. She could well tell Heather out of spite if she reckoned I was trying to get rid of her. Would she risk telling Heather though, knowing the hurt it would cause? I start wishing I’d spoken to Katie properly about this last night.

After polishing off the rest of the bottle of red, we head to bed about midnight and are woken up just after 3 am by Katie coming home. She’s brought someone with her and for the next hour and a half, we lie awake and listen as they have very loud and very energetic sex.

I know Katie is usually fairly quiet during sex and is much more a whimperer than a screamer but tonight she’s cumming at the top of her voice with shouted demands to fuck her harder. The headboard bangs constantly against the wall.

Heather rolls onto her back and stares at the ceiling.

“She’s going to have to move out, Mark.”

I mutter that maybe she’s just a bit drunk and she’s never behaved like this before. Heather rolls onto her side and kisses me. Her hand reaches down and she giggles when she feels my erection.

“Are you getting turned on by listening to my little sister having sex? You dirty old man.”

I protest that I'm not, though it’s the truth. There’s a jealousy I didn’t even know existed eating away at me as I imagine her bouncing up and down on this stranger's cock. Her body bathed in sweat, her little boobs bouncing in time with his thrusts deep inside her. Her head back, howling, crying out for us to hear.

Heather climbs on top of me. “Maybe we should copy them.”

She slides down on my cock. Her pussy walls gripping it, her heat making my cock tingle.

“Maybe I should be as loud as her. We could have a fuck off.” She grins then cries out loudly, “Fuck!! Yesss Mark! That’s it. Fuck me harder.”

I’d laugh if it wasn’t so scary. I don’t know how Katie will react to knowing I’m having sex with Heather but I sense it won’t be good. Heather is bouncing on my cock but it’s like she’s Meg Ryan in the restaurant scene from Harry met Sally.

The noises coming from her mouth sound as fake as the ones coming through the wall. I wonder if they will fake simultaneous orgasms. Images of Heather and Katie swirl in my mind’s eye as Heather rides me faster. She’s bouncing up and down in me but she’s not looking at me. She’s staring at the wall, making loud moans of fake pleasure and I give up. I feel myself deflating again.

I slip out of her but get barely a glance from Heather before she ups her orgasming and starts banging our headboard against the wall as well. Finally, she collapses on the bed in a fit of giggles after a series of loud, high pitched orgasmic wails. I hear a few final gasps through the wall before there is silence next door as well.

I roll onto my side and fall asleep.