She was already soaked when she climbed onto my lap, her bare cunt grinding against my jeans like she couldn't wait another second. "Fuck me with your fist, big brother," she whispered, voice raw and filthy. "Shove it in deep like you own this pussy. No one else gets to wreck me this way."
I didn't waste time with soft shit. I yanked her shorts the rest of the way off and spread her thighs wide on the couch. Her hole was pink, glistening, lips puffy from how worked up she'd been all day thinking about this. "You want the whole fist? Say it again."
"Give it to me. Fist your little sister's cunt until I scream."
I spat on my hand, rubbed it over her slit, then pushed three fingers straight in. She was tight but greedy, sucking them deeper with every thrust. I curled them, scraping that spongy spot inside her that made her hips buck. "More," she grunted. "Four. Stretch me open."
Four fingers slid in easy once she relaxed. Her juices ran down my wrist already. I pumped hard, twisting, feeling her walls clamp and flutter. She grabbed my shoulders, nails digging in. "Deeper, you bastard. Make it hurt good."
I tucked my thumb and pushed. Her cunt stretched around my knuckles, resisting for one hot second before swallowing my whole hand with a wet pop. She let out a broken moan, body shaking. "Fuck yes. Fist me, brother. Wreck that hole."
I worked it slow at first, letting her adjust to the thickness filling her. Then I started pumping, short and brutal, my fist disappearing past the wrist with every shove. Her juices squirted around my forearm, soaking the cushions. She reached down and rubbed her clit hard while I twisted my hand inside her, knuckles grinding against her G-spot.
"Harder," she begged. "Punch it in. Make me come on your fist."
I did. Short, powerful thrusts, my fist pounding up into her soaked channel. Her belly tightened, thighs trembling. She came with a scream, cunt clenching so tight around my wrist I thought she'd break it. Juices flooded out, dripping off my elbow.
I didn't pull out. I kept fisting her through it, slower now, grinding deep while she gasped and twitched. "Again," she panted. "Don't stop until I'm ruined."
We switched positions. She got on all fours, ass up, and I knelt behind her, driving my fist back into her dripping hole from behind. The angle let me go deeper. I could feel her cervix bumping my knuckles. She pushed back onto me, fucking herself on my arm like a desperate slut.
"Talk dirty," she demanded.
"Your cunt's swallowing my whole fist like it was made for it," I growled. "Little sister's hole stretched wide open on her brother's hand. You love this sick shit, don't you?"
"Yes. Fist fuck me harder."
I added a second fist? No, kept one inside and used the other to slap her ass red while I pumped. Her moans turned into one long wail as she came again, squirting around my wrist, the liquid splattering the floor. I pulled my hand out slow, watching her gaping hole pulse and wink, then shoved four fingers back in and made her come one more time just to hear her beg.
Afterward she collapsed, sweaty and wrecked, my arm shiny with her cum up to the elbow. She looked back at me with that filthy grin. "Your turn next. But first… round two?"
I was already hard again.
We weren't done. Not even close.
