Caught - part 2

She opens the door wearing nothing but a towel. Your girlfriend’s sister. She steps back, lets the towel slip, and stands there bare, skin still damp from the shower. You came to see one girl and found the other. The younger one. The forbidden one. Her nipples are stiff. She doesn’t cover herself. Just watches you watch her. She drops to her knees on the hallway rug, reaches for your belt with quick, sure fingers. The zipper comes down. She takes you in her mouth, lips tight, tongue swirling, red hair falling over her face. She sucks you deep, gagging once, then twice, spit shining on her chin. You grab her hair and thrust, fucking her throat while she moans around the shaft. She stands, turns, plants her hands on the wall. Arches her back. Offers herself. You spit on your fingers, work them into her ass, stretching her slow. She pushes back, hungry. When you press the head of your cock against her hole she doesn’t flinch—she rocks onto you, taking every inch with a sharp little gasp. You fuck her against the wall, deep and steady, her tight ring gripping you. Her hand slips between her legs, rubbing fast. She comes with her face pressed to the plaster, knees shaking. You pull out just in time. She drops, opens wide, tongue out. You paint her lips, her cheeks, thick ropes that drip down her chin onto her small breasts. Down the hall a key turns in the lock. Footsteps. Your girlfriend’s voice calling your name. The girl on her knees smiles, cum still glistening on her skin, and wipes her mouth with the back of her hand.