The metro car is packed, but the stranger's eyes find the girl in the seat ahead, her ass perfectly framed by her tight jeans. He moves closer, his eyes never leaving her curves. She shifts, giving him a better view, a small smile playing on her lips. The train lurches, pushing him into her. He takes the opportunity, his hand sliding up her thigh, feeling the heat between her legs. She gasps, pushing back into his touch. He's hard now, his cock straining against his pants. The train stops, and they're alone. He unzips, and she grinds against him, her ass cheeks clapping against his cock as he fucks her in the crowded, anonymous city, the train's motion setting the rhythm.