Contrary to popular belief, the hump is not the seat between driver and shotgun. That is the bitch seat. The hump is located behind the bitch seat, where there often is a hump in the floor, thus the name.
Mike: "Well, then, I take wingman."
Bill: "I'm too tall for backseat driver or hump, so I take bitch. Put the dog in the cargo bed."
Thanks man, your a good backseat driver and thanks for the tip, I'll get right on that.
Jane: Stop being a bitchy back seat driver.