"I do want to say that the original idea is more like "how much the conditioning and repeated fucking is affecting him and wants to indulge even for a moment" than "he's an inherent slut wanting to let loose.""
Fair enough, and that is a different thing. But for the most part I've settled into the path of normal, gradual corruption/loss of control, and then if it goes on long enough, "new" Mezz, altered in how he sees the world (Not needing the ear clips with the boars in GT, normal eyes at the end of GT when serving Mahir etc). Again, the engine of the whole thing is the tension between "old" Mezz and the "new" version that's gradually eating away at him in each scenario. If the old version willingly gives in, then that destroys the tension. And if you mean the point at which the new version gains enough control that "he" starts doing things "voluntarily", then...again, that's pretty much the Mahir scene at the end. Sorry for being so difficult, but in my mind at least it snaps to one of those two binaries: either he's being slutty (which doesn't fit), or he's been fully trained/corrupted, which is awesome, but already in the games. For me, the point at which he starts "willingly" giving in/asking for it/going along with it/submitting is the point where "new" Mezz crosses the threshold into having more control than not. So there's never really space for "old" Mezz to do that.
Glad you're not annoyed though, I do enjoy the chance to be forced to actually explicitly think through why I'm doing certain character or story things sometimes, though it can be a little like trying to consciously remember the steps of tying shoelaces.