1. n. A step up from facepalm. When shit has really hit the fan, or fails or epic fails are piling up to the point beyond cussing and a facepalm. An example situation would be when your computer is lagging incredibly.
2. v. The act of biting one's fist on the grounds of the first definition of this term.
Man, that dude's about to snap. Did you see him fistbite?