Lyric discussion by jmlrugby11 

Cover art for Heartbeat lyrics by Childish Gambino

I think he's singing about a "friends with benefits" type of relationship.

My Interpretation

He's singing about an ex-girlfriend "Are we dating?Are we fucking?Are we best friends?Are we something in between that?" Often thoughts you get after a relationship. Your girl still wants you around even when she has a boyfriend sometimes she'll cheat if the moments right and she'll still claim you're her best friend. Because she thinks that shit will make you wait around until she figures out if she wants to come back to you or not.