I've looked into it.
The game has two components to control the up and down motion you do with the webcam.
The first is the scene manager. It contains 5 different calibration steps that essentially calibrate to get a minimum and maximum Y value to work with, with minimum being essentially calibrated to 0.
All of these are within a switch case, and reference each other. The end of one case starts the case after, returns, then breaks.
The game then has that y value tracked by the camera's calibration information when you move what it calibrated to up and down, thus controlling where you are penetration-wise.
I tried bypassing all the calibration by essentially getting rid of it within the switch case that uses it, and shoving input.mouse.y as the value it looks for instead, but it really doesn't like that. It can't seem to skip to the play mode without having done the calibration first.
It's entirely possible I'd somehow have to get it to take a minimum and maximum Y value from the mouse and somehow pipe that in so that it then gets the y value from the mouse, and then you could get it entirely translated to using a mouse instead of the motion of your hand on your dick for Google to enjoy looking at.
I'd have to look into it further eventually.
Let me get pictures of the areas in question within Assembly-CSHARP.dll real quick.