A person who actively takes part in incestious relationships.
A person who actively takes part in perverted sexual acts and relationships.
Originated in Utah after polgamy and incest was banned in the 1800s.
Didn't you know Jason was an aist? He was married to his sister for two years before the government found out.
Ass in seat time. Experience, especially as it relates to motorsports.
"Hey old man there is no way you're going to be able to wheel that stock jeep through those heinous rocks!"
"Oh yeah n00b? I got some serious AIST, Hold my beer, your about to be pwned!"