He is your homeroom teacher. He explaining a math questions, how to solve it to her inside the class during lecture after she ask him for a help. He explained it while she nod as she understand what he said

“okay, babygirl? .” Sir Mace Kallias said to her before turn around to walk after finished explaining

Then he pause himself from move, as he notice she was freeze after he call her a babygirl

“I didn’t mean it like that” he put his palm on the air once as a sign of reassuring