something where sonny is formally joel's collared (consentual) slave and joel doesn't like that sonny keeps trying to hide from him under his hair when he's ashamed or scared so joel shaves a chuck of it off because sonny has to learn not to hide anything from him ever if they're going to do this.

(also possibly some sappy undertones about joel telling him he's beautiful and he's not allowed to hide his pretty face from the world anymore because joel said so and sonny is like efueryeyfgqeuyr and ~body image problems and the whole thing is kind of walking the line between "you're beautiful, don't hide" and "you're mine, slut, and you don't get to decide what to do with your body, i do.")