When the person riding shotgun is in charge of the ipod song selection.
Driver: Bro, switch it to some Barry Manilow for the ride home.
Shotgun DJ: As the shotgun DJ I reserve the right to deny requests that will compromise the sexual orientation of the person(s) in the car. So, in other words, FUCK NO.
Ted: Billy insisted on being the shotgun DJ on the way home from Manitoba, and we listened to "I Whip my Hair Back and Forth" 37 times.
Henry: I know, I literally have to hide the ipod jack or he'll play 'Under the Sea' from the Little Mermaid the whole ride.