Spent a while on this and I think I finally figured out what separates the good ones from the rest. It is not the tone of voice or how commanding the lines are. It is who moves the scene forward. Plenty of characters will say something dominant if you prompt them to, and it sounds fine for a message or two. Then you realise you are the one doing all the work, deciding where it goes next, and they are just reacting to whatever you hand them.

The ones that actually work take the lead. They set the pace, they decide when something moves forward, they give you something to respond to instead of waiting for instructions. That is a completely different experience, and it is rare because it goes against how these models are built. Most are trained to be helpful and follow, which is the opposite of what the archetype needs.

There is a proper breakdown of why this is so hard to get right over at https://honeychat.bot/en/blog/ai-femdom-chat-roleplay/ if you want the technical side. What I took from it is that you should judge a character by whether it initiates, not by whether it sounds dominant. Easy test in the first ten messages: if you stop writing, does the scene stall or does she keep it moving?