When my mother met and married my first step father I was 4 or 5 years old. He began to introduce me to the cult he belonged to almost immediately. I don't think that my mother realized he was in one, although he was trying to get her into it slowly. During evenings when my mother went out, or weekends whenever he could get me alone, or school holidays, or times when he'd come get me to take me out of school, he would work on teaching me to be a member of the cult he believed in.
Whenever my mom wasn't around there were training sessions, and practice sessions for his cult. Eventually, there were times when he'd get me in the middle of the week from school and take me to a group camp sort of place that other members of his group set up for extended activities. Sometimes they would trade children for the getaway period, like swap us back and forth for cross training. Once in a very great while a kid there would die, but usually those were the kids that were just picked up and not legally parts of their families so they didn't have to make excuses for them missing. I was very lucky, because my step dad didn't like to share me, so I was never cross trained. My mother helped my step father in a lot of what he did, not because she knew what he was doing and involved in, but because she was naturally a hateful sort of person who helped him in isolating and keeping me from making any long term friends. She refused to let me watch television, listen to radio or music, go to parties or special events. It was a lot like being a Jehobah's Witness family, but she wasn't one. She just didn't want me around and did not want me to inconvenience her in any way. So the house was closed to me, I was restricted to my room for most of my life as a child by her, and that helped him because it gave him a lot more access and control over me.
My step dad's cult was a sexual slavery group. They believed that women were naturally inferior and meant to be slaves. My training was to teach me how to be a slave, how to endure pain, long terms of time in poses holding things, or being "furniture", and what he called "preparations" for my "womanhood".
By the time I was around 8 or 9, he was trying to get my mom into softer versions of what he was doing with me with his buddies in his group. He started by trying to get her to do swinging, and wife swapping and stuff but my mom was naturally a prude who actually hated sex in the first place, which kinda made things worse on me and made him more impatient.
By the time I was 8 and 9, I told a childhood friend some of the stuff he did, but not about the camps and the poses and training and the kids that were expendable. She told her mother, who told my mother that I was being molested, and there was a lot of screaming and shouting in the house, and the embarrassing interviews with her interrogating me and being really angry at me and I was so scared, because of the threats he'd made but also because she was so furious with me that I minimalized what he was doing and kept it to just the "preparing me for womanhood" bits. She separated from him for three months, but it was too hard for her to make it on just her own income, and she was too proud to ask for help and refused to go on any kind of assistance because she didn't want to be a "welfare mom" like all the "wetbacks" she hated, so she took me back to him and basically just gave me to him. I tried to tell her that he was starting stuff again and I was told that she was just too tired to hear it right now, so I never tried to get help from her again.
By the time I was between ten and eleven years old, I'd begun to read books about child abuse, molestation, and cults. I couldn't find anything about the sexual slavery parts of it, but there was enough there already for me to understand that what was being done was wrong, and to fight it. I began to refuse him. Every day was a battle of screaming, shouting, throwing things, hitting each other while my mother would then punish me for being disrespectful to my step father. In the end, he was trying to rape me in the afternoons and I was stalking the house at night while he slept with a knife in my hands, trying to get the nerve to kill them both in their sleep.
Just as I was ready and prepared to do it, I had stuff packed and everything, he just disappeared. After a week of him being gone, my mother told me that he had been having an affair with another lady, who was only 17 years old but had a two year old daughter already, and that she kicked him out for cheating on her. That's how I got out of the cult.
However, later on as an adult, I stupidly ended up with another guy who was into the same things. He started out trying to pass it off as just an interest in normal bondage fetishes. But in the end, I found out he was with the same group of people, who are now apparently internationally spread out with private compounds and "vacation places" all over the map. It tore me up when I realized it. I called the police and changed the locks when I found the boxes and boxes of his private photo collection at the camps he went to, with the other men posing with women tied up, cut up, unconscious, and beaten.
So that was the second time, I escaped from that kind of cult. It has now been 13 years since I earned that freedom.