It's not quite as clean as that. It's knowing that a person won't hurt you deliberately without a good reason, and that they won't like hurting you.

It's not about never being rough with each other. It's about agreeing (largely implicitly) how rough you are going to play, and knowing that if you say, "Stop that! It hurts!", the other person really will stop.

My complaint against Bad Facilitator was not so much that he played too rough, but that he ignored me when I said he played too rough. He never attempted to moderate his behaviour to what I considered to be the inviolable heart of good manners.

I used to think a good relationship was one in which we never hurt each other. I now believe a good relationship is one where we can talk about hurt and try to avoid it in future, yet forgive accidental injuries.

Trust means, if they stand on your foot, you know they're being clumsy, not malicious or callous. And when you point it out, they'll get off and apologise. (I had this conversation with my T, but I'm not sure she agreed.)