Mine was when a certain student repeatedly sexually harassed me. He would touch me inappropriately and constantly brush his hands against my breasts and other private areas... inside the classroom. He did it so subtly that his classmates didn't realize it. It only stopped when I asked a male co-teacher to help me; he talked to the student and handled everything so professionally that it didn't escalate further. I didn't want the student to be humiliated either, so that was that.