Here is a way to fool people that you are cracking your nose and really freak them out:
Put your hands together like you are praying and hold your nose between your fingers. The trick that they cannot see is that you hook your thumbnails behind your front teeth, and when you move your hands like you are cracking your nose you pull your thumbnails forward so they make snapping noises as they pull out from behind your teeth.
People get really grossed out at this stupid human trick.