What is Back Seat Betty?
A female who frequently has sex on the first date or first encounter.
Britney: Hey Lohan, did you call that guy we met at the coffee house yesterday?
Lohan: Yes, we met for drinks and well sex this morning.
Britney (laughing): Sometimes you can be such a back seat betty.
Nicole: Paris, did that guy give you a ride home from the club last night?
Paris(smiling): Yes, you could say that he gave me a ride last night.
Nicole: Your family should have been in the automobile business, because you are such a back seat betty.