Grimes, have you ever seeing a football player really drive a ball with his head?
If so, this is what you want to do. Really smash your forehead/hairline into the dude's face - he will not appreciate it.
I'll have to disagree with my brethren & ghost7 here.
Headbutting is perfectly acceptable.
In fact, hitting someone in the balls, biting, gouging etc is all perfectly acceptable.
You have to remember, the aim of 99.9% of fights is to win & take as little damage as possible. Fight like you're in a life or death situation & you will almost always win......it's hunger people.
*starts shadow boxing to Eye Of The Tiger*