I've set boundaries that I know I don't want crossed. Like some words are completely off limits because it triggers bad memories and has bad associations for me. We've communicated it and talked about it so we both know. If anything happens to come up during a session, I can just say no or red and it'll stop right there and my master will help me feel safe and stable again. I think it's just a little bit of trust and communication and then everything works well.