And then something remarkable happened. The crowd — just about evenly divided between men and women — instantly segregated itself: the men were propelled as if by a centrifuge toward the room’s perimeters, and the dance floor, a platform raised just a step off the ground, was taken over entirely by women surrounding Freedia. The women did not dance with, or for, one another — they danced for Freedia, and they did so in the most sexualized way imaginable, usually with their backs to her, bent over sharply at the waist, and bouncing their hips up and down as fast as humanly possible, if not slightly faster. Others assumed more of a push-up position, with their hands on the floor, in a signature dance whose name is sometimes helpfully shortened to “p-popping.”

http://www.nytimes.com/2010/07/25/magazine/25bounce-t.html