The room fills with the scent of ammonia as he pees, his cock straining against the wet fabric of his underwear. He strokes it desperately, the friction sending waves of pleasure through him. He pauses, opening his eyes to watch as a rivulet of piss runs down his leg, pooling on the floor. He closes his eyes again, his imagination running wild as he fucks his hand, fantasy partners replacing the empty room. His breath hitches, his body tenses, and with a final, shuddering groan, he comes, adding his cum to the mix of fluids staining his clothes.