The back side of camel toe. It's when a girl wears pants so tight that the ass crack is clearly defined. Most often a girl with camel toe will have ass toe as well.
Alex: Damn, check out that girl's ass.
Jay: Holy Shit she has some nice ass toe.
Whilst in the 69 position (girl on top), if the girl is too short while performing oral sex and grinding on the man's chest, she will eventually engulf the man's neck with her ass and create a suction force that leaves an "ass hickey."
Dude last night I saw Andy and Hannah sixty-nining in the park and this morning he had an ass hickey on his neck!