I'll keep this short. I already typed out something really long, but I thought it was overly-detailed...
There's this guy in my school (Sophmore in high school). We're not really friends, but he sits next to me at lunch most of the time. Well last friday, a girl sat next to me, she normally sits on the other side of this guy but he was late getting to lunch. When he got there, he promptly pushed all of her stuff, including her food, into her usual seat. I quickly told him she was sitting there. He told me "Shut up, the b*tch can move over one seat." This shocked me. She slowly started to slide over, when I told her to stop. I told her "The douche can find a new seat, don't move." He didn't take too kindly to my "douche" remark. He went on about how he was "sick of my crap", I've had to tell him to chill out before. It ended in me calling him a jerk too many times, him grabbing me by my collar, and a teacher stepping in before things got ugly (for him :P).
My question is, did I handle this in a (gentle)manly fashion? What could I have done better? And lastly, what should I do if this happens again (because it has already, and it will again)?