Hey man, I can totally relate to your story. I used to get physically and emotionally abused by my sister. She was two years younger so it was very humiliating but she was very sportive and was in the girls rugby and soccer teams. She would fight dirty and knew where to kick me during fights and constantly threatened to turn me into a girl all the time and gave me fake kicks (if didn’t kick me there). She gave me a girl name and When we were alone or were with her friends and cousins, she would also dress me up, put make up on me and tease me that this is how I would look like after she is done with me. I have also developed all types of fetishes now and it turns me on being dressed up by my partner and being humiliated. I am in therapy but have accepted that I need humiliation to get turned on. I read it is a way of coping mechanism so our brain turns something traumatic into something pleasurable to deal with it.