if it was the first time he acted like this, and you and the three other guys had been making fun of him and joking at him for a while...well, I guess it really can happen even to 'the best ones' to lose their temper.
Your other friends actually having to hold him is pretty scary though.
Do you think he might have tried to actually punch you or hit you? Swearing and threatening, I can understand (and he has my sympathy here) but phisically harming you is too much.
Was it the very-very first time you were teasing him for his pick up lines-or about girls in general?
Or there is an history of him being joked at?
Is he a shy person, and does he usuallly have problems asking girls out?
I like his pickup lines, by the way.
Does he joke at you and the other guys, too?
Or is he usually the target of jokes?