The horny passenger, his cock aching with need, starts a slow, teasing rhythm. The train's hum vibrates through him, intensifying his pleasure. He pictures the busty woman across the aisle, her eyes locked onto his exposed flesh. His strokes quicken, his grip tightening. The train lurches, sending shockwaves through his body. He gasps, his cock throbbing, as he paints the carriage wall with his milky seed.