It's the funniest thing in the whole wide world! Pretending to put your balls in the mouth of a fresh corpse is hysterical!
I'm obviously kidding. I can't stand people who teabag. It's not funny at all and if you do, I will most likely avoid you. What's worse is on Gears of War 2 when you're crawling and instead of executing them, you just stand next to them desperately trying to teabag.