[quote name='LiquidNight']I never yell it, and no one else ever should either, much less combine it with some kind of gesture to make it look more ridiculous.[/QUOTE]
For real. I've had my brother Hobocorpses yell it at me during head to head play, and it makes me feel hot murderous rage in my veins.
Usually the middle finger, or the other 'offensive' middle finger-esque gesture when you bend the right arm up at the elbow and slap the bicep with your left hand. Don't forget the bared 'Fawk yeh' teeth either. We horses are good at that.
I picked arm pump, I don't say booyah (unless I'm making fun of booyah). In fact that last time I heard someone seriously say booyah was about 6 years ago and he was shamed (he did more of a "I'm punching an invisible midget in the face" move too).