Btw, if you're taking suggestions, buttplusg go well with cages, and I have plenty of ideas on how to utilize one in the context.
Alongside this, I quite like the idea of the King's cum being used as a game mechanic, perhaps with some of kind of capacity/edging mechanic, and a x-ray/ view screen of his capacity?
Also potential run ins with the nun, with features such as ruined orgasms, a sounding rod that blocks your cum, etc.