I never planned to fuck my sister while she was bleeding, but once it started there was no stopping it. We were both twenty-three, living in the same cramped apartment after our parents moved away, and the tension had been building for months. It was her period that finally broke us.
She came out of the bathroom that morning in nothing but a thin white tank top and panties. The crotch was already stained dark red, a wet patch spreading down one thigh. "I'm leaking through everything," she muttered, not bothering to hide it from me. I was on the couch, trying to ignore the way my cock twitched at the sight.
"You need help with that?" I asked, voice low.
She looked at me for a long second, then nodded. "Come here."
I followed her to her bedroom. She peeled the panties off and lay back on the towel she’d spread across the sheets. Her pussy was slick with blood, lips swollen and glistening. The smell hit me—thick, metallic, mixed with her usual musk—and it made my mouth water. I stripped fast, my dick already hard and leaking.
I climbed between her legs and dragged my tongue up her slit without hesitation. The blood was warm and coppery on my tongue, thicker than usual lube. She moaned and grabbed my hair, pushing my face deeper. I licked her clit in steady circles, swallowing everything that came out of her. It tasted like her, but dirtier, more forbidden. My chin was coated in red by the time I pulled back.
She reached down and wrapped her fingers around my cock, smearing blood along the shaft. "Put it in me. Now."
I didn’t need telling twice. I lined up and pushed inside in one slow thrust. She was hotter than usual, her walls gripping me tight while the blood made everything slick and obscene. Each stroke came out streaked red. I watched my cock disappear into her again and again, the wet sounds filling the room—sloppy, messy, perfect.
"Fuck, you feel so good when you’re like this," I growled, picking up speed. She lifted her hips to meet me, blood smearing across both our thighs. Her tank top was pushed up so I could suck on her nipples while I pounded her. She tasted salty and sweet, and every time I bottomed out she clenched around me.
We switched positions. She got on all fours and I took her from behind, watching the blood drip down her legs onto the towel. I reached around to rub her clit, my fingers sliding easily through the mess. She came hard, her whole body shaking, a fresh gush of blood and cum coating my cock as I kept thrusting through it.
I flipped her onto her back again and hooked her legs over my shoulders so I could go deeper.
The angle let me see everything—her swollen clit, the red ring around my shaft every time I pulled out. I fucked her faster, chasing my own orgasm, the wet slap of skin on skin getting louder.
When I came, I buried myself to the hilt and filled her up. The mix of my cum and her blood leaked out around my cock as I stayed inside her, both of us breathing hard. She reached down and scooped some of the mess onto her fingers, then licked them clean while looking me in the eye.
We didn’t talk much after. I pulled out slowly and watched the thick white and red mixture spill from her. She pulled me down for a kiss, our mouths meeting with the same metallic taste still on both our tongues.
That became our routine for the next few days. Every morning and night I’d eat her out until my face was painted, then fuck her until the sheets were ruined and we were both shaking. She’d ride me sometimes, grinding down so the blood coated my balls and thighs. Other times she’d jerk me off onto her stomach, mixing my load with the mess already there before we showered together.
By the time her period ended, we’d crossed every line we could think of. The apartment smelled like sex and iron for days afterward. We never stopped after that. Even when she wasn’t bleeding we found new ways to be filthy together, but those heavy, bloody days stayed our favorite. We both knew it was wrong. We just didn’t care.
