The kitchen table was covered in open textbooks when I walked in. My little sister, twenty years old and looking frustrated as hell, sat there in a tiny tank top and shorts that barely covered her ass. "Mike, can you help me with this stats homework? I'm fucking dying here."
I dropped my bag and sat next to her. She leaned over, tits pressing against the table, and pointed at the problem. Her hair smelled like vanilla and something sweeter. I started explaining the formula, but my eyes kept dropping to the way her nipples poked through the thin cotton. She noticed. Instead of pulling away, she shifted closer, thigh brushing mine.
"Keep going," she said, voice low. "I need it explained real slow."
My cock twitched in my jeans. I kept talking, but my hand rested on her bare knee. She didn't move it. A few minutes later she was grinding her leg against my fingers, breathing harder. "This is so wrong," she whispered, but she grabbed my wrist and pushed my hand higher until I was cupping her pussy through those tiny shorts. She was already soaked.
I shoved the books aside, yanked her shorts down, and spread her legs right there on the chair. "You want your brother to help you? Then shut up and take it." I buried two fingers in her tight cunt and pumped them hard. She moaned loud, head thrown back, hips rocking against my hand. Her juices ran down my knuckles while I finger-fucked her until she came, thighs shaking.
She dropped to her knees without being told, ripped my zipper open, and sucked my cock into her mouth like she had been waiting all semester. Her tongue worked the underside while she took me deep, gagging but not stopping. Spit ran down my balls. I grabbed her hair and fucked her face until I was throbbing.
I pulled her up, bent her over the table, and slammed into her from behind. Her pussy gripped me like a fist. "Fuck, your brother's cock feels so good," she gasped.
I pounded her hard, the table legs scraping the floor, her ass rippling with every thrust. She came again, screaming my name, and I didn't stop. I flipped her onto her back, hooked her legs over my shoulders, and drove in deeper, watching her tits bounce while I used her.
We moved to the couch next. She rode me, grinding her clit against me, dirty-talking the whole time. "Fill your sister's pussy, Mike. Come inside me." I grabbed her hips and thrust up until I exploded, pumping thick loads into her while she clenched around me and came one more time.
Afterward we stayed tangled together, her head on my chest, both of us catching our breath. The homework was still scattered on the floor, forgotten. She smiled against my skin. "We should study together more often."
