I didn't always have erotic feelings my T and tried to trace back to when they first started for me. They kind of crept up on my I think but I think they mainly started it was when I finally started to trust him a bit more and let him in. There was a day early in where I was also was talking about my H and difficulties we were having he asked me an appropriate question relating to our sex life which I felt awkward about. The question was fairly unremarkable and not inappropriate in the context of what we were talking about but I think it was the moment things changed for me.
On a day to day basis, the feelings are there most sessions. They do tend to flare up when he is more attuned and I feel more connected to him for sure.