A girl who is average looking (like Plain Jane), but willingly uses her butthole to go up in society to counter her aesthetic deficiency. This is common in Catholic schools, and self-esteem is virtually non-existent.
Biff: "Dude, is Jane lifting her anus up at that he-she over there?"
Vladimir: "I can't tell, but it's staring at her."
Biff: "My God... She's an Ane Jane!"