The rumble of the tracks and the rhythmic clacking of the wheels against the rails provide a steady beat for the passenger's illicit dance. His fingers dance over his zipper, freeing his throbbing cock, as the train's motion rocks his hips gently. The cool night air whipping through the slightly open window contrasts with the heat building in his lap, as he strokes himself to release, the city lights blurring into a kaleidoscope of color outside.