I never planned to fuck my sister, but once it started there was no stopping. It began the summer after she turned eighteen, when she moved back into our parents' house while finishing community college. I was twenty-three, living in the basement apartment, working nights at the warehouse. Late one humid night she came down in a thin tank top and panties, saying she couldn't sleep. We talked, drank a couple beers, and before I knew it my hand was sliding under that tank top, cupping her small breast while she moaned into my mouth.
"Jake, we shouldn't," she whispered, even as her legs spread for me on the old couch. I pulled her panties aside and found her already wet. My fingers sank into her tight pussy and she bucked against my hand, biting my shoulder to stay quiet. "Just this once," she said. But it wasn't once.
The next night she came back. This time I bent her over the arm of the couch and shoved my cock into her from behind. She was slick and hot, gripping me like she was made for it. I fucked her hard, slapping her ass, telling her how good her cunt felt. She came with a muffled cry, pushing back to take every inch. When I was close I asked if I should pull out. "No," she gasped. "Come inside me. I want to feel it." I flooded her pussy that night, and every night after.
We got reckless. She'd sneak down after Mom and Dad went to bed, or we'd fuck in her room while they were downstairs. She'd ride me slow, rolling her hips so my cock dragged against her walls, then slam down hard until I pumped another load deep into her. Some mornings she'd wake me with her mouth, sucking me until I was throbbing, then climb on and take me bare. "Fill me up again," she'd beg, eyes glassy. "Make sure it takes."
It took. Two months later she missed her period. We stared at the positive test in the basement bathroom, hearts pounding. Instead of stopping, it made us hungrier.
The risk of her growing belly only turned us on more. She'd straddle me, hand on her still-flat stomach, and whisper, "Your baby is in here because you can't stop breeding your sister." I'd thrust up into her, gripping her hips, telling her how her pregnant tits were going to look, how I'd suck milk from them while I fucked her swollen pussy.
By the fourth month her belly had a soft curve. We couldn't keep our hands off each other. She'd come down after everyone was asleep, strip slowly so I could see the changes, then sink onto my cock with a long sigh. "Feels so full already," she'd moan, riding me while I rubbed her belly. I'd flip her onto her back, spread her thighs wide, and pound into her, watching her tits bounce and her stomach shift with each thrust. She'd come hard, clenching around me, and I'd follow, shooting thick ropes of cum against her cervix, making sure my seed stayed where it belonged.
We kept going right up until she started showing too much to hide. Even then we'd find quick, desperate fucks in the garage or the laundry room, her belly pressing against me while I drove into her from behind. "Don't stop," she'd pant. "I want you to fuck me until I have this baby." Every time I came inside her it felt like claiming her all over again.
Now she's six months along, glowing, belly round and heavy. We still sneak off whenever we can. Last night she lay on her side on my bed, one leg lifted, and I slid into her from behind, slow and deep. My hand rested on her belly while I moved inside her. "This is yours," she whispered. "All of it." I came with a low groan, pumping another load into her pregnant cunt, feeling her walls flutter around me as she came too.
We know it's wrong. We know we can't stop. And neither of us wants to.
