Nice, this would be my dream game! Having a big dick myself, I can assure you the struggle from the girls trying to deepthroat you is a HUGE turn on hehe. The game also needs a lot more gag sounds and tears >:) (I can provide the sound effects if you want, just tell where I can send).
Another questions/suggestions: does the dick "disappears" when it enters the girls mouth, like SDT? I assume not since this is a 3D-physics engine. So that means there should be a limit to how big the dick can be. Could you maybe create a size limit to how long a dick the girl is able to deepthroat and anything bigger than that sticks out of her mouth, while she just winces and gags? (maybe make an optional checkbox like "limit DT by size"). That would also be super realistic and hot. And could you make the resistance bar reset if the dick stays out of her for a while (like SDT)? And this is also a suggestion: resistance and pleasure bars for the guy and girl. Also, would it be possible to create an "x-ray vision" to make the girl (or parts of her) transparent, so you can see how far the dick goes into her (also like SDT)? And do you plan to create sex poses on the future? Of course, using all the resistance rules from above lol >:)
Sorry for the loads of questions, but I'm sure this will soon be very popular and it will be hard for you to answer everyone. I'll put money where my mouth is: just donated you $5 my man. Even though this is equivalent to like 40 bucks on my shitty country and the project is early, I believe in you.