i managed to add more key frames into the anime shader. For this mod i merged an orgasm animation into it.
The orgasm is automaticly controlled by a timer, whose frequency is relevent to the speed of piston. In another word, orgasm occurs more often with higher piston speed.
You can adjust the duration of normal/orgasm period in the ini file. However i'm not directly telling you how. You're encoureged to read the code and find out how it works yourself.
Alt+v to show the speed control slide bar.
Alt+←/→ to decrease/increase speed.
Alt+p to pause the animation.
] to force an orgasm.
Mod file is also archived in the origin mod collection.