OK as a Martial Artist for the past 20 yrs and an instructor.. this is how you handle the aggresive, stupid , paranoid wanne be Alpha. The point of this is control. Never EVER react in the prescribed way, this demonstraites you as reactionary and not in control of the developing situation. Keep your cool, always be nice, now that does not mean you can't neg but don't be an ass and don't directly insult. This alone should prevent the situation from developing into a fight.
As martial artists if you allow it to develop into a physical altercation you have already failed and should take a long hard look at what you did wrong. Now this will do a few things for her, one it shows you are not afraid of the cave man and if you never allow it to be know your a fighter they will wonder what you know that they don't. This keeps the attention subtly on yourself while the bricks for brains proves he's a retard. Example. wanna be AMOG puffs up and tells you he going to kick your ass, look him square in the yes ( functional challange) then ask him calmly. Dude whats that going to prove?
There is no intellegent answer to this question, if he even opens his mouth he has just screamed ' IM A MEAT HEAD".

or you can turn to the girl or even to his male friend if there is one there and ask " is he always this emotional? "

just a few thoughts

Silk

imo, i think u should try to avoid fights.instead act as though ur the gentleman in the case. girls like gentlemans in any case, if he tries to hit u or something, reply with something like.. dude,theres no need to get so serious about this. or something. try not to sound aggressive, but at the same time, avoid being a wimp