It won't hurt right away. Give it about 30 seconds. Use it how ever you see fit, but remember, it's only funny when it hurts your friend, not you.
This is a neat trick that will cause severe pain, and a red mark. You don't really need much for this, a stick of Big Red, some saliva, and a high tolerance to pain. You'll need: -A stick of Big Red Brand chewing gum -The wrapper from the gum