When someone who is normally a smart ass is currently not saying or making a face which would normally be interpreted as being a smart ass.
David Jones is a prime example of resting smart ass face when he isn’t speaking.
It's a Brazilian expression used to describe a person who is very lucky in life.
In a period in time where a caesarean delivery was not a commont practice, a baby who was born legs first (beeing pulled by it's legs first and not by it's head) usually would not survive the operation, so any baby who was born legs first (with his ass facing to the moon) and survived was considered lucky
I can't believe he won that car, he was definitely born with his ass facing to the moon
When your face looks like a hairy ass
"Damn bro you look like ass face mcgee" "Wow you have ass face mcgee"