1. FAT ASS FINGERS: a name given to one because of their hilariously oversized, sausage-like fingers
2. Acting in a way that just fucks up the situation.
Extremely popular in the Buffalo suburbs.
Fafs are often seen in pictures giving the shocker
Note: despite the fingers, fafs still manage to get laid.
"Dude, get your fafs out of my drink"
As the faf drives by a hot girls house, he points out the window with the fafs yelling, 'yo, is that her house' As this happens the girl walks outside thus embarrassing everyone in the car. He has committed a faf, or we say he faf'd it up.
Also common is the faf of the night. This occurs when one drops a beer, soils themself, gets their fake id taken or any other fuck up.