Yeah, that is sort of what I was thinking. Cleaning out and injecting oneself full would likely be experienced as a submissive behavior. On the other hand, since it would be done prior to session, couldn't the dom/sub relationship be protected?

Doms often advertise with language indicating their desire to curate the perfect scene a sub seeks. So the nature of the relationship is hazy to me because the fun lies in serving her impulses, not the other way around.

I think your ability to take defecation on your face is terrific and I'm glad you are able to enjoy that much, even if you can't go all the way. I hope your mistress gets real satisfaction from it.