From the movie "Breakin' All the Rules". Pay attention to what he says about being able to bite your own hand.

.... go ahead and try it... "You want some hot sauce?!"

When Snickers asked me how he could show me that he really loved me, I responded by telling him to bite through his hand. He said he could do it but I told him to save it for when he proposes to me. "If you can't bite through your own hand than you can't have my hand!"