In my third martial arts class with Zhenzan, they came up to me from behind while we were doing a drill and touched the back of their hand  to my perineum. The back of their fingers touched my scrotum. They walked up behind me and whispered in my ear: "Back of my hand, trust me" and less than a split second later did it. The timing between the two was incomprehensible, and there was absolutely no way for me to consent or agree. It was unexpected and caught me off guard. I was so traumatized and felt so violated I didn't know what to do, so I just kept training. That was not acceptable. There was no reason to do it. I was disturbed. I hope I never see them again.