I found my sister's Tumblr by accident. One night I was jerking off to the usual incest tags when a new post popped up from a blog called "siswantsbro". The words hit me hard: "I want my brother to bend me over and fill my pussy with his cum until it leaks down my thighs. Brother sister cum pussy sex is all I think about." The photo was her ass in tiny shorts, the same shorts she wore around the house.
My cock got rock hard instantly. I knew it was her. Same background, same tattoo on her hip. I messaged her that night from my own secret account. "Your brother would fuck that pussy raw and pump it full."
She replied in minutes. "Prove it. Come to my room right now."
I walked down the hall with my dick already tenting my boxers. She left the door cracked. Inside she was on the bed, naked from the waist down, legs spread, two fingers sliding in and out of her wet pussy. "Lock the door," she said, voice low and dirty. "Then come eat this cunt like you promised on Tumblr."
I dropped between her thighs and buried my face in her. She tasted sweet and hot. I licked her clit hard, then shoved my tongue inside her hole. She grabbed my hair and ground against my mouth. "Fuck yes, brother. Suck that pussy. Make it drip for your cock."
I pulled back, spit on her slit, and rubbed my thumb over her swollen clit. "You want brother sister cum pussy sex? You want me to fuck you stupid and fill you up?"
"God yes. Do it. Fuck me like those stories."
I stood, yanked my boxers off, and slapped my cock against her wet lips. She was shaved smooth and glistening. I pushed the head in slow at first, then slammed the rest of the way. Her pussy gripped me tight and hot. She moaned loud. "That's it. Stretch your sister's cunt."
I started pounding her. The bed creaked. Skin slapped. Every thrust made wet sounds as her pussy got sloppier. She reached down and rubbed her clit fast. "Harder. Fuck me harder.
I want your cum deep."
I flipped her onto her stomach, pulled her hips up, and drove back in. Her ass cheeks spread wide. I watched my cock disappear into her again and again. "Look at this greedy pussy taking her brother's dick," I growled. "You post that shit on Tumblr and now you're getting it for real."
She pushed back to meet every thrust. "Fill me. I want to feel you shoot inside. Brother cum in sister pussy. Do it."
I reached under and pinched her nipples while I fucked her faster. Her walls started fluttering. She came hard, pussy squeezing and pulsing around my cock, juices running down my balls. I didn't stop. I kept slamming until my own orgasm built tight.
"Here it comes," I warned. "Taking every drop."
I buried myself to the hilt and unloaded. Thick ropes of cum pumped straight into her. Pulse after pulse. She moaned the whole time, grinding back to milk me. When I finally pulled out, my cum spilled from her stretched hole and ran down her thighs exactly like she described in her post.
She reached back, scooped some on her fingers, and licked them clean. "Again," she said, rolling onto her back and spreading her legs wide. "I want more brother sister cum in this pussy before the night is over."
We fucked three more times that night. Doggy, on her side, and with her riding me while she read her own Tumblr posts out loud. Each time I filled her until she overflowed. By morning her sheets were soaked and her pussy was puffy and leaking.
We never talked about stopping. Every night after that she messaged me new filthy ideas straight from her blog. I delivered every single one. Her cunt stayed full of my cum, just like the stories she loved.
