When a girl has a butt that just looks fucking fantastic in pants, but once the pants come off it has so many craters it looks like an astroid.
Can also sometimes been seen when wearing very tight skirts.
Example 1
Girl 1: Ugh, she has such an astroid ass! Everyone thinks it looks so nice, but it's really not that nice!
Girl 2: I know dude, I saw that shit in the locker room the other day!
Example 2
Student 1: Dude, Ms D has such a nice ass!
Student 2: It's not that nice dude, wait until she turns around in that tight skirt. That shit's an astroid ass!
one who is in the continual state of having a stick up their ass; one who is such a tight ass as to have become the stick up others' asses; one who is exceptionally uptight, exacting, pretentious
All the kids in my class are so pretentious. Today in class they were all worked up over that assrod, Jacques Derrida.