When I dreamt about my T raping me I brought it up in session cause I felt betrayed and angry at my T and discussing it helped with that. I said only what I was comfortable with (practically no details) and my t was more concerned about the emotions I felt than any action/facts that had happened. Plus, obviously, we discussed why I have these nightmares about ppl I feel close to.
Other than that I don't have any sex fantasies re my T. If I had, I think discussing it might be helpful but the way you phrased it feels a bit, idk, weird? Like tell me how you'd like to be touched, what would you do to me... TMI and honestly how does it supposed to help YOU?
I don't want to be paranoid here but to me it looks like the T could be getting off these fantasies...