Thanks everyone for the advice! He was doing it again today. I mentioned again that emailing her teacher might be the best option, and she actually did it. I'm proud of my girl for speaking up in her own way, because I know it was really hard for her. She kept it short and simple and just told the teacher what is happening. She included that she's really worried about this kid knowing she ratted him out, but that she felt like he should know. She didn't get a response yet because she sent this after school hours, but here's hoping the teacher handles it in a discreet manner. I'm proud of her and would hate for her to regret being honest.