“Fuck yes! Cum inside me. Shoot your, oh yessss, cum deep into my womb. Make my stomach swell with your seed. Blast my, oh Oh OOHH, ovaries with your cum.”

“I, unngh, think, umph, you might, oh fuck yes, need to improve your knowledge, FUCK, of anatomy.”

“At least I, OOHH fuck, can find the clit.”

“Oh. Are. You. Not. Enjoying. This?” He slowed right down, thrusting in time with his words for emphasis.

“Fuck no, don’t stop. No no no.” I couldn't bear him stopping.

He laughed smugly. “That’s what I thought.”

“Fuck off, and, fuck, impregnate me, ooh fuck, you dickhead.”

“You’re on the, ooohh god, pill.”

"God, I fucking hate you.”

Mark grinned down at me. I’d known that grin for eighteen years, and it had never once meant anything good.

“Don't lie. You love me.” He punctuated his words with a thrust that knocked the headboard against the wall.

“I love your, oh god, cock. There’s a, oh fuck, there’s a difference.”

“That’s the nicest thing you’ve ever said to me, Smelly Nellie.” He had called me that since we were 5 and had used it to make me cry. It had since become his favourite name for me. I dug my nails into his back and raked them down. I grinned as he hissed and his hips stuttered and I felt skin bunch up under my fingers. 

“Just shut up and, ungh, fuck me, Marky.”

“Don’t call me, nngh, Marky.”

“Don’t dish it, ooOOHh, out if you can't take it. Marky Marky Marky the Farty.”

“You’re … eighteen," he struggled to get out. He was sweating with the effort of thrusting into me. 

“Eighteen and … a half.” I corrected, struggling to get the words out as he pounded into me. 

“You’re such a child.” He said, rolling his eyes as he clasped both hands behind my neck and pressed his forearms down across my upper chest, pinning me into the mattress. He started thrusting much harder, pulling me down into him as he thrust forward into me.

“OoooHHh FUCK! Yes!” I moaned as his cock slammed into me. His sweaty forehead pressed against mine. I saw him grin that smug fucking grin again, pleased at making me moan like that. 

So I sank my teeth into his shoulder, where the muscle was thickest, and bit down until he swore. I couldn't stand the smug smile.

“OW, you feral little FUCK, Nellie.” He retaliated, grabbing my nipple and twisting it. I gasped, thrusting my chest into his hand. 

“Harder,” I demanded, refusing to admit any pain.

He twisted until it really, really hurt, and my moan became more of a whimper. “Yeah. That’s what I thought,” he growled, twisting a little harder before releasing it.

“Prick.”

“Slut.”

I bit his shoulder again, and this time he grabbed a fistful of my hair and yanked my head back.

“Stop biting me!”

“Make me, you, oooh fuck, make me you, you ooooh god…” I trailed off, giving up trying to think of an insult as he cupped my chin with his hand. Running his thumb roughly over my lips, smushing them sideways before pressing his thumb forward into my mouth. I loved when he did this. My lips closed around it and my tongue pressed up against him. I sucked on it, letting out a breathy groan as I looked him right in the eyes. 

“Fuck,” he breathed.

He pressed down harder on my tongue, pushing my jaw open. He groaned, and his rhythm got sloppy for a second.

“You’re, mmph, you’re a, ahhh, waaAannker.” Everything came out garbled around his thumb and the way he was fucking me.

“What was that? Couldn’t, ooh, hear you with my thumb in your gob.”

“I shed, nnh, you’re a, mmph, wanker.”

“I don't need to, uuugh, wank; I've got a nymphomaniac as a sister.”

“Shu’h up Marky.” I bit his thumb, just to be a bitch. He pulled it out, wet with my spit.

“You’re a child, you know that?”

“You’re, ooh, yesssss, you’re the one with your cock in, ahhh, me. If I'm a child, what does that…make you?” I struggle to finish the sentence.

“Will you just shut up!” He groaned as he put his hand over my mouth. I licked his palm, making him roll his eyes, and pushed his thumb back in between my lips.

“Suck it like the baby you are.”

I sucked it and looked up at him with big eyes.

“Good girl.” His patronising tone, making me shiver, will delight. But I'm nothing if not contrary. 

“You’re ‘thuch a, mmph, you’re thuch a...” I tried to get out an insult. But his thumb was pressed firmly on my tongue. 

“Such. A. What?” That smug fucking grin. That smug fucking shit-eating fucking grin. I refused to let him win.

“A knn...ghhh...” I tried again, but I was cut off as he pulled his thumb out of my mouth and wrapped his hand around my throat instead. He squeezed, and my breath cut short. Fuck. I wasn’t going to let him think he was in control. I grabbed his wrist with both hands and pulled down, pulling him tighter against my throat. He felt me pull and squeezed harder, and my vision got fuzzy, and I couldn’t breathe, but I was still going to fucking tell him he could fuck off.

“Ffff...kkk...yhhh...”

I tried to force the words out with no air behind them but couldn't. So I freed one hand from his wrist and flipped him the middle finger. He laughed so hard it shook his whole body, and I felt it in his cock.

“I thought that might, oooh, shut you up.”

He loosened his grip. I dragged in air, gasping. “Fuck...you...Mark.” He tightened it again. I hated him and I never wanted him to stop.

He kept releasing his grip, just often enough to let me gasp in some air before gripping harder before I got the chance to insult him more.

When my eyes were watering and my brain was starting to get foggy, he must have noticed something because he let go of my throat, and I sucked in air, and before I’d finished the first breath, he was kissing me, and I was kissing him back and biting his lip. 

“You’re a, uugh, psycho,” he grunted, biting my lip in return. I planted my foot on the mattress and tried to roll us, trying to get on top, while he was distracted, and for about half a second I had the momentum. But then he slammed me back down to the mattress, knocking the air out of me. He grabbed my legs and pushed my knees up and back towards my chest and held them there, taking full control of my body; he was so much stronger than me. It wasn't fair.

“Nice try, Smelly Nellie.”

“Control freak.”

“Brat,” he growled as he started to pound into me suddenly, making me yelp loudly into his ear.

“Fuck Nell. Mum and Dad aren’t home, but the, oooh fuck, neighbours are.” He pushed his thumb back into my mouth. “Suck it, you little gremlin. Maybe this time it will keep you quiet.”

“Harder!” I moaned around his thumb.

He rolled his eyes and pulled back until he was barely inside me and drove forward with a mighty thrust that shoved me up the bed. Then he did it again and again. Pausing between each one before thrusting with everything he had.

It hurt. Each thrust landed with a deep bruising impact. Every thrust shoved me up the bed, and he dragged me back down and did it again.

“Harder!” I would die before I admitted my body was screaming at me that it was too much.

He ignored me. He continued to pull out, pause, and slam back in. My thighs were shaking against his arms.

“That, oooH, hard enough for you?”

“I’ve had, nnf, harder.”

“No, you haven’t. You’ve, oooh, only ever fucked me.”

“Yeah and, oh fuck, you’re shit at it.”

“So you haven’t had, nnh, harder.”

“Oh fuck off!” Jesus fucking Christ, he was infuriating. He was right though. He was the only person I’d ever fucked and the only person I probably ever would. 

He was thrusting so deep it felt like he was pushing into my stomach. The pain and the pleasure had blurred, and I was whimpering with every thrust. “Faster,” I begged, around his thumb. My voice came out smaller than I wanted.

He ignored me again; he just kept that same brutally slow pace. The pause between each thrust was worse than the thrust itself because I knew what was coming and my body was bracing and wanting it at the same time.

“Faster! Oh GOD! Harder!”

“Say please.”

“Fuck off.”

He stopped. He was thrust deep inside me, pressed against my cervix, completely still, and took his thumb from my mouth. 

“No, no, no, fuck, don’t you dare.” I needed him to keep going. I was so close. I was desperate. And he knew it, the bastard. 

“Say please.”

“Please, oh god, you absolute wanker!”

“Mm. I don’t think you mean it.” He shifted his hips, barely, just a tiny circular motion that drove me wild. “Say something nice about me.”

“You’ve got a, oh god, you’ve got a big cock.”

“Less sarcastic.”

“That wasn’t sarcastic! You have a big cock! It’s your only redeeming quality.”

He slid out, leaving just the tip still inside me, poised to thrust back in but just held there as I strained my hips towards him. 

“Mark. Mark, please.”

“What are you?”

“What?”

“What. Are. You?” Each word punctuated by a tiny teasing thrust. 

I knew what he wanted. This wasn't the first time we had played this game. “I’m...I’m a cumslut.”

“Whose cumslut?”

“Your cumslut. I’m your, oh god, cumslut, Mark. Now will you please for fuck’s sake FUCK ME!” I screamed the last part. 

He let go of whatever restraint he’d been holding onto and drove into me relentlessly. His cock was hammering into me, making the bed creak and groan.

“Oh god, oh god, oh fuck, oh, oh, Mark, fuck, I, ahhhn.”

“Still think I’m, ooh, shit at this?”

“You’re, oh FUCK, Mark; I can’t, guh.”

“Yeah, that’s, oh Jesus, that’s, fuck Nell, ahhh, you’re so, ugh.”

“Mark, I’m, oh fuck, I’m, I’m gonna, mmph, I’m so close; please, oh god, please.”

“Yeah? Cum on my, oooh, cum on my cock, Nell. Fucking nngh, milk it.”

“I’m, I’m, oh god, oh god, oh FUCK, Mark, MARK, cum in me, please, ahhh, please cum in, oh OH.”

“Nell, oh fuck, Nell, I’m, nngh, FUCK.”

“Yes, yes, yES, YES, YESSSS! AAAhhhhnnngh.” I moaned into his shoulder. My whole body pulsed around him, wave after wave, and my hips were bucking up against him as I climaxed. I bit into his shoulder again without really planning on it. I could feel my pussy spasming in long rolling contractions as my legs trembled and shook. “Oh FUCK, Mark, oh fuck oh fuck oh fuck.”

He kept ramming relentlessly into my cunt. “Nell, oh fuck, Nell, oh god, FUCK,” he was nearly shouting too. He slammed into me and I felt my brother's cock jerk inside me as his cum pumped into me. He was shaking as hard as I was, and his arms were trembling where they held my legs.

“Pump it deep, ohh, deep into my ovaries.”

“That’s not… fuck… that’s not how it works,” he panted.

“Shut up,” I gasped, grinning.

He collapsed on top of me. I ran my hand through his hair; it was soaked with sweat. I could feel his heart hammering in his chest and just how heavily he was breathing. I loved pushing him to his limit, and judging by his heartbeat, he was seconds away from a heart attack. I was going to say so, but in my head I pictured him saying in that stupid smug fucking know-it-all voice, “That's not how it works!”

Instead I decided on, “Get off me, you fat fuck!” I tried to push him off with absolutely no success.

“Fuck off,” he chuckled, leaning in and kissing me, our lips mashing together as I struggled to breathe. If anything, he seems to be getting heavier as I pressed my hands into his chest trying to shift him, squirming my body to try to get out from under him.

He broke the kiss, laughing at my attempts to make him move and pinning my arms down, so I bit his ear. He yelped and rolled off me. 

I immediately missed his weight on top of me, which I would never tell him because he’d be insufferable about it. We lay there side by side, breathing hard. My thighs fucking ached. My throat was raw and tender. I could feel his cum leaking out of me onto his sheets.

I checked the clock on his bedside table. Shit. It was 11:22. Mum and Dad would be back at half past. They had caught us together last year, and it was bad. But try as they might, you just can’t keep twins apart. I loved how Mark made me feel. I was utterly addicted to the prick's prick. 

However, I really didn't fancy a repeat of last year's hassles, so I hurriedly grabbed my dressing gown off the floor. "Bye, loser,” I shouted over my shoulder as he lay on the bed still breathless, his glistening cock softening. 

I slipped out the door before he got a chance to respond and crossed the hallway to my room. I pulled on my pyjamas and got into bed with his cum still wet between my thighs and pulled the duvet up to my chin. I could shower in the morning. I went to sleep with my brother's cum drying on my skin and inside my cunt. It helped me dream good dreams.