Why not just have an option for letting them cum inside, collecting it, or even allowing you're privates to try and hold it in? Adding options is better than not adding anything at all
I assume you meant to quote something else I said.
The answer to any "why not" question like this is that I'm a single individual so all work on the game is essentially zero-sum. I could spend time developing a system where the character attempts to hold a creampie inside and make that into some type of status or something and I'm sure it'd be hot and some people would enjoy that, but actually adding something like that is a lot more work than it sounds like; even the current status system (the game tracks hygiene, nudity, reputation, hunger, lust, notoriety, etc and tries to have dynamic reactions to these states as you play) requires
tons of bespoke content to be written and implemented to manage things like NPCs reacting to nudity and stuff. Tracking creampies feels like it's too narrow in its appeal and wouldn't meaningfully contribute to the verisimilitude of the world, and implementing it would take time away from other content.
That said, I
do want to add creampies. Version 0.4.0 was just released to patrons and will be available in a week, and it includes creampies in the encounter system. They're basically random right now, but I
may let the player choose (or encourage her partner to choose) internal or external cumshots in the future. This would require a rewrite and refactor to some parts of the encounter system to allow it, though. It's not a huge priority right now (it's just not gonna happen before February), but I will definitely get to it.