1. something totally awesome or cool. used to show happiness, or a good expression.
2. about half-way up someone's body, there is a region called the "ass". also used to state that someone has a "Sweet Ass". sweet in this case usually meaning hott.
an insult derived from a compliment to a woman with a nice ass. when directed towards a male who has spent time in the slammer it implies that he was fucked up the ass by bubba, hence "sweet ass"