The train screeches to a halt in the dimly lit station, the sudden stop causing the woman to fall into her stepbrother's lap. She doesn't move, instead grinding her ass against his crotch. He grips her hips, guiding her movements, his cock hardening against her. Their breaths hitch in unison as he reaches up to palm her breast through her dress, his thumb brushing against her nipple. She gasps, her hand reaching back to stroke his length through his pants, their eyes locked, lost in their taboo lust.