I've found myself in the position of being a Bull for my ex and her husband. He's a willing submissive cuckold who is happy to perform acts of service including cleaning up and being a chauffeur. We regularly check in with each other and he is absolutely loving every scene I have with his wife, and I am, of course, more than happy to plow his wife and give her all the pleasure he cannot. It's a mutual relationship. My ex (the wife) and I have a very friendly platonic relationship that happens to be kink-friendly due to our history and she is the one who approached me with the idea of being the Bull in her relationship.

Every time I'm with the wife I pay my due respects to her ass with my tongue. She used to be very coy and play like she didn't like it (acting pouty while she turns over, pulling her panties down and spreading her cheeks and telling me not to, etc.) I've checked in with her several times and she does admit that she is playing with me. I've been putting in at least 20-40 minutes rimming her every time we meet up and she likes it more each session. She told me she is not on board for anal "yet", but I feel like I'm making some progress. When we were together 9 years ago we would do anal every Sunday as sort of a morning ritual and we both enjoyed it very much, so this won't be her first dive into it.

The first piece of the puzzle is to have us enjoy anal consistently again. It's obvious that the more I play with her ass, the more she is getting back into the groove, but I want to keep this momentum up without her potentially losing steam for the idea. I'm struggling to figure out how I can keep the trajectory without sacrificing my power dynamic with the cuckold. My first approach is to pitch the idea for him to finger her ass so he can get her ready for me when we have our next session, but I'm sceptical that will work since the wife does not pay him very much attention sexually (ex: no oral for him and very little PIV).

Does anyone have any ideas or has anyone been in this situation before? Can any Bulls give me any guidance?