Phrase taken from the 2004 movie "The Girl Next Door." Can be used when disscussing sexual exploits, excessive drug usage, great plays in sports, a good book, and nearly anything. That's What A Man Does can be said at anytime when describing nearly anything that a man would do. Also, That Is So NOT What A Man Does can be used as a phrase of discontent towards something your buddy has done that offends you (ugly chicks, forget to pay you back for beer, etc.)
Me:Dude, I got so crunk last night I did two chicks at once on the roof.
Shane: YEA BABY THATS WHAT A MAN DOES.
Me:Except one was like 300 pounds and the other had backne like mad.
Andrew: No dude, so not what a man does.