Trenton Booster Seat
When you sit on someones lap in the backseat of a car, and allow yourself to be sodomized so you can still watch the drive-in movie screen. Often used to reference a method of payment for being taken to the movies which includes demeaning sex.
Melanie badly wanted to go see a new summer blockbuster at the drive in, but didn't have the money. So she used a trenton booster seat to get a dirty old cabbie to pay her way.