Empty carriage, only the rhythmic clatter and sex underwear. She locks the door, strips, and straddles the seat facing the window. Moonlight paints silver across her skin as she chants “sex underwear” in time with the rails. Four fingers stretch her open; the wet slap echoes louder than the train. “Everyone outside, see sex underwear come,” she gasps. The train enters a tunnel—darkness swallows everything except her rising “sex underwear, sex underwear, fuck, sex underwear!” until she explodes, soaking the leather in a flood of unstoppable “sex underwear” release.