Just read your comment below that it was an intentional decision to not give the sub a cumming scene and I totally see your point lol.
But I think making it an option would be even better, cuz that's just one more thing you, as the Dom, can control about your boy toy. It's up to you whether he experiences pleasure or pain, and that, I think, is the fun part of being a Dom ;p
Or you can make it so that he can only cum hands free from getting fucked... while he is locked😈 For player's part, you can allow players to set whether the MC has a penis / a strap-on to do the topping.
This aside, I want to say the whole game is indeed really well made! Especially the details. I experimented some more w/ the combinations between toys and actions and I was surprised how much I missed at first. Like w/ the watersport plug, I didn't know you could fill the sub up w/ it and then let it leak out. So for real, kudos to you for your attention to detail on each scene!