Backseat jiver

Someone who isn’t in control of the music that’s playing at a party or in a car, but is suggesting a new song every time a song ends, often one that nobody else there likes. ANNOYING

Sarah: Hey, can we play some Red Hot Chili Peppers?
Me: No! We decided I was the car DJ for this trip!
Ethan: Yeah, Sarah, stop being such a backseat jiver!