The other thing that you are dealing with right now is YOUR OWN Nice Boys Don't (force themselves on women) pathogenic belief. This means that you have your own sense of guilt to deal with here, and it's tempting to find something wrong with the fact that she loves it when you take her, and so do YOU.
That's exactly what runs through my head.
I gave myself a zero for the Fellatio Inquisition. I figure it was bad to ask, but it was good to react well, and to thank her. And I will go forward as you advised, because hey, she has a safe word, right? She can stop the train any time she wants to get off. I'm just playing a role.