The act of vigorously whipping your dick back and forth (left and right) so that it makes contact with your legs. The resulting impact produces a smacking sound, and if done rapidly, it can sound like clapping.
Instead of clapping with his hands at the end of the show, George stood up, dropped his pants, and started penis clapping like a boss.
by Cactus92 November 14, 2011
when two nude men stand facing one another and thrust their pelvises causing their penises to fly forward making contact and emitting a percussive sound.
by external vagina November 01, 2009