A quote made famous for its use in season 1 of Supernatural. Implies that the driver of a vehicle chooses what music they and the passengers will listen to while whoever is riding shotgun must stay quiet.
Sam: You gotta update your music collection. Black Sabbath? Motorhead? Metallica? It's the greatest hits of mullet rock.
Dean: Well, house rules Sammy. Driver picks the music, shotgun shuts his cakehole
a kind of cuddling that can often be found in the summertime between co-counselors at a summer camp when they have had a long day with their campers and simply wish to cozy up in their cabin.