What is Fartass?
1.
Just a random insult. Combining "Fart" and "Ass." Or accusing one of passing too much anal gas. Not an insult to be taken to heart, however. Fun times.
"Hey, John, how about you stop farting, you fartass."
2.
Putting your butt-hole on a dolphins blow-hole
Did you just fartass that dolphin?
See