My art skills are not good enough to do that and I don't have the time to refine them to be able to do that; would if I could
Even if you had the skills I don't see an elegant/non time consuming solution to the floating dick "problem" (because I too want to see those titties during BJs goddamn it)
I tried my hand at it by placing the dick on top of an amorphous flesh mound/pelvic region but while it works for some girls/scenes it all starts falling apart when you have to make adjustments and then implement the code for all the specific variations (at least with Oni's version of the game).
In this regard I'm looking forward to your Godot port/remake, if you don't mind I would love to write a mod for it.