He was dared to tell you that he loved you, even though he didn't, but before he could say it was a dare, you accepted his feelings and started dating him. At first, he hated it, but now, he's started to actually catch feelings

It was the middle of the night, and you snuck into his room, and laid with him, accidently waking him up

"Mmm... oh.. nghh.... what are you doing..?"