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