In the sultry climate of Mexico's Expo Sexo 2012, the scent of sweat and sex permeates the air. Vendors hawk their wares, from leather harnesses to massive dildos, as attendees engage in open displays of affection and desire. In one corner, a couple locked in a passionate embrace, her dress hiked up, his hand buried between her thighs. Nearby, a group of friends watch a live demonstration of impact play, the sharp crack of the whip mingling with the submissive's moans. The energy is electric, a tangible force that binds the crowd together in a shared celebration of carnal pleasure.