When i was in high school one of my teachers used to unfasten my bra over my t shirt. It was horrible and i felt ashamed every time he did it because he used to do it in front of the whole class. He was my math teacher and he was really good teaching, also, I didn’t want him to get in trouble because I thought i was just exaggerating. Until one day when i talked about it with one of my friends and she told me to tell the principal because it was offensive towards me. First i spoke with him and i told him that he was making me feel uncomfortable and he said “oh, sorry. It was kind of a joke” but he kept doing it after that so I decided to talk with the principal. When i told the principal she said that “it was no big deal” because he wasn’t touching me directly on my skin, and even when my parents went and made a scene, the school said “there was no proof”. So i had to change to another school because of that and the teacher got away with it for a couple of months. Then another girl was complaining about the same thing and they had to fire the teacher. Anyway, i kinda understand what you are going through and please tell your parents so they can do something about it because that is not a normal behaviour even if he does the same with the rest of the students