To tip in a sarcastic way in an effort to make the bartender feel like "he's the asshole".
Bartender: $20.00 please...
Pat: Here you go
(Pat hands a $20.00 bill, bartender smirks)
Greg: Whoa man he just got pissed your not gonna tip him
Pat: Well I am going to, I was looking for some more money.
(Pat put's a $2.00 on the bar)
Pat: Twwwoooooo dolllaaa tip here! We got a twwwwooo dolllla tip here!
Greg: Droppin the sarcastip kid...nice.