The gym goes quiet as the last member enters, the sign on the door flipped to ' Closed.' The owner, a rugged, tattooed man, locks the door and turns to face his eager patrons. "Ready to work up a sweat?" he asks, stripping off his shirt. The room erupts in a chorus of 'Yes, sir,' as they follow suit, their naked bodies pressed together in the steamy, intimate space. The air is thick with testosterone, the sound of flesh slapping against flesh echoing through the room as they give in to their primal urges.