AITA for telling a boy to stop trying to hit my breasts.

I am a 15 year old girl and am a B cup. I am chubby. I am not overweight, but I am not skinny. I am about 155 lbs and 5'6". <br><br>Last week, at school my friend was bullying me. He is just joking but this joke has been going on for a while. I have asked him to stop but he won't. <br><br>What he does is as he walks by me, he hits my breasts. <br><br>When I asked him to stop, he said "You don't even notice", but I do. I also asked him again this week to please stop and he refused. <br><br>On Friday, he did it again. I said loudly, "Can you fuck off? I asked you to stop" and a teacher heard. She said that language like that is not acceptable and gave me a detention. I told her why I said it but she said it doesn't matter. <br><br>My mom was mad at me instead of the boy. Like it was somehow my fault that he keeps hitting me. <br><br>AITA?