Underbender
While standing behind an unsuspecting fella, who is preferably deep in conversation or thought, one would reach a hand through his legs upward, grabbing the top of the belt buckle and in one swift, smooth and forceful motion pull down and back and watch the poor gent either smash their face in the ground or complete a front flip. Be prepared to run.
Geoffrey had been egotistically running his mouth all day, so when I noticed he was taking a few pictures with his haggard harem, I swooped in and administered an unforgettable underbender, on film.