This sounds oh so familiar to me. A few additional suggestions to add to the growing list of good advice you already have. Sir and I prefer the stoplight system to a single safe-word when trying new things and pushing boundaries. That way I can let him know where I'm at easily. We use yellow as a check-in point. Sir will check-in as we go along asking what color I'm at, and I can also call out a color at anytime if I need/want.

Another thing that helps me deal when things are really intense is good aftercare. I cannot talk about a session directly after, instead I found I needed to be petted and reaffirmed for awhile then left alone for a bit to process before I can talk it over. The aftercare part helps me separate in-session from not and also he makes sure to tell me how much he cares about me and how special I am to him during these times. We then talk after I've processed by myself and can explain better my experiences and he will ask questions and share his experience as well. When I was very new I found that hearing what he liked and got out of a session helped me let go and feel better about admitting what I liked without the shame. I mean what could be so wrong about having wonderful, hot, mutually fulfilling sex and playtime with someone you care about? Who cares what that playtime involves, as long as you are both happy that is all that matters.

It sounds as if you are finding your footing pretty well so far. All the best to the both of you, I hope you enjoy the journey. Feel free to message me if you want to talk more ever - kuri