A
girl who is really only interested in a guy because he has a nice
car, and it gets him attention, so she wants in on that attention and uses her ass as a free ticket to the
car.
If played right by the guy with the ride, he gets to rail a girl outside of his reach because he does have a nice
car (or truck... something shiney, tasteful and/or loud)
"Use me for the ride, I'll use you for the hide"
-Sir Mix-A-Lot