In the grimy, cramped toilet, the solo buck laces his fingers behind his head, eyes closed, lost in fantasy. His cock, already hard, tents his pants. He unzips, spitting into his palm before wrapping his hand around his shaft. The train's motion rocks him, his hips thrusting into his fist. His breaths come ragged, the sound of his handjob filling the small space. Suddenly, the door swings open, revealing a curious onlooker. Caught in the act, he doesn't stop. His strokes become frantic, his cock pulsing as he paints the toilet with his cum, a lewd show for the stranger's wide eyes.