My Sister and her best friend

The cab's headlights cut through the dark like a drunken stumble, pulling up to our house at 3 a.m. sharp. I heard the giggles before the door even slammed high-pitched, sloppy laughs that echoed off the quiet street. Mia, my 19-year-old sister, and her best friend Sarah tumbled out, both of them shitfaced from whatever dive bar they'd hit after hours of shots. I was 15, wide awake in my room upstairs, but curiosity dragged me to the front door. Stepping outside in my boxers and a t-shirt, the cool night air hit me, but the real heat was watching them stagger across the lawn.

Mia was a mess her short black skirt hiked up, showing the curve of her ass cheeks, and her top half-unbuttoned, tits spilling out like they owned the night. Sarah, blonde and curvy in tight jeans and a crop top, was right behind, her arm slung over Mia's shoulder. They were laughing hysterically at nothing, probably some inside joke from the bar, their voices slurring into nonsense. 'Oh my god, Mia, remember when ' Sarah started, but dissolved into another fit of cackles.

A second later, Mia's legs gave out. She face planted onto the grass with a thud, skirt flipping up completely to expose her black thong wedged between her pale cheeks. She was out cold, snoring already, her chest rising and falling in heavy rhythm. Sarah, still chuckling, wobbled over to a flower bed and squatted down, yanking her jeans open. A hot stream of piss arced out, soaking the petals, the sharp smell mixing with the earthy night scent. She didn't even bother pulling her panties aside just let it flow right through the fabric, darkening the crotch of her jeans.

I stood there, heart pounding, my cock twitching in my boxers as I watched. Sarah glanced up, eyes glassy, and grinned like she didn't give a fuck. 'Hey,' she slurred, recognizing me in the porch light. 'Your sister's a lightweight.' But then she teetered sideways, collapsing onto the wet grass beside Mia, her jeans still unzipped, the piss puddle spreading under her.

Emboldened by the alcohol haze and the forbidden thrill, I stepped closer. Sarah was babbling now something about the cab driver and a spilled drink her words tumbling out incoherently. My hand moved on its own, sliding between her thighs. Her pussy was warm and slick, not just from the urine but from whatever arousal the night had stirred. I pushed two fingers inside her cunt, feeling the tight walls clench around them. She gasped, babbling cutting off into a soft moan, but her eyes fluttered, heavy with booze.

Urine still trickled out in weak spurts, warm against my knuckles as I pumped my fingers deeper. The taste of it all hit me salty, musky and I couldn't resist. Dropping to my knees, I leaned in, tongue flicking out to lap at her folds. Her clit was swollen, peeking from under the hood, and I sucked it hard, the mix of piss and her juices flooding my mouth. Sarah's babbling silenced completely; her body went limp, head lolling to the side as sleep claimed her. But her hips bucked once, instinctively, before she passed out cold beside Mia.

That was it the spark that ignited everything. My cock was rock hard now, straining against the fabric. I'd jerked off to thoughts of Mia before, sneaking peeks when she changed, but this? This was real. I yanked my boxers down, freeing my throbbing dick, and turned to Sarah first. Her jeans were loose enough; I tugged them down her thighs, exposing her shaved pussy, lips puffy and glistening. Positioning myself between her legs, I rubbed the head of my cock along her slit, coating it in her wetness and the last drops of piss.

I thrust in hard, burying myself balls deep in one go. Her cunt was tight, hot, gripping me like a vice even in her unconscious state. I pounded into her relentlessly, the slap of skin on skin echoing in the quiet yard. Her tits bounced under the crop top with each slam, nipples hard points against the fabric. I came fast too fast grunting as I shoot my load deep inside her pussy, cum spilling out around my shaft. But I wasn't done. Pulling out, I flipped her over onto her stomach, ass up in the air. Her hole winked at me, and I spat on it before pushing my still-hard cock inside.

Fucking her ass was even tighter, the resistance giving way with a pop as I sank in. I gripped her hips, bruising the skin, and reamed her deep, feeling her body jolt with each thrust. Another orgasm built quick, and I unloaded there too, cum dripping down her crack as I withdrew, spent but raging with lust.

Mia was next. My sister, snoring softly on the lawn, oblivious. I rolled her onto her back, spreading her legs wide. Her thong was soaked blood streaking the fabric from her period, the metallic scent hitting me. I didn't care; it only made it dirtier, hotter. Ripping the thong aside, I saw her pussy, swollen and leaking a mix of blood and arousal. My cock, slick from Sarah, plunged right in. The warmth enveloped me, the slickness from her cycle making it slide easy despite the taboo.

I fucked her pussy hard, watching her face for any sign of waking, but she just snored through it, body rocking with my rhythm. Blood smeared my shaft, mixing with my juices, but I kept going, pounding until I felt the build-up again. Pulling out, I aimed for her ass tight, untouched as far as I knew. I pressed in slow at first, then rammed home, her hole stretching around me. The friction was intense, her period blood lubing the way unexpectedly. I came inside her ass, pulsing deep, marking her in the filthiest way.

Hours blurred after that. I went back and forth between them, dragging Sarah on top of Mia at one point, their bodies tangled in a heap. I fucked Sarah's mouth while fingering Mia's bloody cunt, then switched, shoving my dick down my sister's throat until she gagged in her sleep. I came on their faces, in their hair, painting streaks of white across their drunk, passed-out forms. Sarah's pussy took another round, her ass too, until she was gaping slightly, cum oozing out. Mia's holes got the same treatment pussy filled despite the flow, ass stretched wide.

By dawn, my penis was raw, throbbing with overuse, finally going soft no matter how I tried to stir it.
The sun peeked over the horizon as they started to stir, but that's a story for another time.