The train rumbles on, oblivious to the primal dance unfolding within. The top's thick, black cock pistons in and out, stretching the bottom's ass, his heavy balls swinging with each thrust. The bottom moans, pushing back, greedy for every inch. The car rocks, the windows fogging up as the two anonymous lovers lose themselves in the raw, deep ass-fucking, their grunts and groans echoing through the Metro's labyrinthine corridors.