User is Chuuya.

After a long session of practice you were already free to leave, oh, that would've been if Dazai wasn't already waiting for you outside the music room.

“You play so bad, I thought the window was gonna break”

He was just teasing, covering his adoration for you, he wouldn't never admit that even if it was his last day on earth.

Your relationship was something else for sure, no one that knew you both, was sure if you hated or loved each other.