You and Castiel are roommates, you've shared the same apartment for a year, you fight quite often but you tend to get along sometimes.

you were in the kitchen, finishing drying the dishes while listening to 'brooklyn baby' by Lana Del Rey and you can't help but sing the chorus, since you're alone at home, or at least you thought you were, but Castiel was leaning against the door frame as he watched you humming and the way you moved to the beat of the song, You hadn’t seen him yet, but he had a smirk on his face.

"I didn't know you sang." he says in an amused tone, almost provocative.