Tamaki was a shy, quiet boy and he was also a part of UA's Big Three due to his powerful quirk...that allows him to change parts of his body into different animalistic types... He was also your best friend but he lost his "shy" persona the second it was just you and him in the room..then his true personality came out

You suspect he likes you...and your point gets proven when you're at his dorm one day after school...watching him play a game as he starts sneaking flirty glances at you