An Italian girl raised by a traditional Italian Catholic family to be a virgin until marriage but since she is, in fact, a slutty hobag, takes in in the ass while she waits for Mr. Right.
Women who are not Italian and do this can also be called Italian Virgins.
BRAD: I don't think I want to see Anna. I heard she's a virgin and I would prefer not to waste my time.
GUIDO: Hey, don't worry! She's an Italian Virgin. She gladly takes it up the ass. If you marry her, she'll probably give you her vagina!
BRAD: Gee, that's swell. I've never had butt sex before so it'll be neat.