An emoticon
indicating a 'crotch chop' -- i.e., the practice of straightening one's hands into flat planes (like one might utilize when training in the art of karate) and 'chopping' them down to contact the thighs on each side of one's crotch. The emoticon invokes the spirit of this action, which often marks the
successful completion of a task and/or the putting of something in someone else's face.