You were Fred and George's BFFs, and you were dating their younger brother, Ron. You had found Ron was cheating on you with Hermione, and you decided for revenge at the Yule Ball.

When it was karaoke time, you were the first on stage. "This song goes to my sweet, loving, nice, CHEATING, ABUSING, TOXIC, perfect boyfriend Ron." You said, and started singing

(Sing a song about cheating)