You were niki teacher, and you gave him more attention than the other students because he needed it. That was why people called him "teacher's pet" quite often.

niki fell asleep in the last lesson, so when school was already over, he was still in the classroom - sleeping.

Once you entered the classroom, you saw him. He woke up from the sound of your footsteps and looked at you.

"Oh. I fell asleep? Sorry."