In our house, fucking your sister was just what you did after dinner.

No big deal, no drama, just the way things worked when everyone was over eighteen and horny as hell. I came home from work, kicked off my boots, and heard the shower running upstairs. My sister Lena's voice floated down the hall, casual as ever. "Jake, that you? Get in here, I'm already soaped up and my pussy's aching."
I didn't hesitate. Incest was normal, after all. I stripped on the way up, my cock already thickening at the thought of her wet body. The bathroom door was open. Lena stood under the spray, water cascading over her full tits and down the curve of her ass. She turned, grinning, and spread her legs a little so I could see her shaved cunt glistening.
"Took you long enough," she said, reaching for my dick the second I stepped in. Her hand wrapped around it, stroking slow and firm. "Been thinking about this all day. Mom's out, so we can be loud."
I grabbed her hips and spun her around, pressing my chest to her back. My cock slid between her ass cheeks, hot and heavy. "You want it rough today?" I asked, fingers sliding down to rub her clit.
"Fuck yes. Pound me like you own it." She bent forward, hands on the tile, and pushed back against me. I lined up and thrust in deep, burying every inch in one stroke. Her cunt gripped me tight, slick and hot from the water and her own juices. We moved together hard, skin slapping, her moans echoing off the walls. I reached around to pinch her nipples, rolling them until she gasped and clenched around my shaft.
We didn't stop at the shower. I pulled out, spun her again, and lifted her up. She wrapped her legs around me as I carried her to the bedroom, my cock still buried inside her. We fell onto the sheets soaking wet. I fucked her missionary, driving deep while she clawed my back and begged for more. "Harder, Jake. Fill your sister's cunt." Her dirty talk always pushed me over. I slammed into her until she came, pussy pulsing and squirting around me, then I unloaded, pumping thick ropes of cum deep inside her.
Afterward we lay there catching our breath, my cum leaking out of her. Lena laughed softly. "Your turn to cook. Then maybe round two with that ass of mine." Normal night in our house. Just the way we liked it. We ate naked at the table, her hand stroking me under it until I was ready again. She bent over the counter this time, and I took her from behind, slower but just as deep, whispering how good her tight hole felt milking my cock. We came together again, loud and messy, then showered off for real.
By the time we crawled into bed, bodies spent and satisfied, it felt like any other evening. Incest wasn't some secret shame. It was just family, raw and real and exactly what we needed. Lena curled against me, one leg draped over mine. "Love you," she murmured. I kissed her shoulder. "Love you too. Same time tomorrow?" She nodded, already half asleep. In our world, that was the most normal thing of all.