::EDIT::
So apparently there is a tool called VMDSizing to properly transfere a motion with the original model to another model, without any clipping.
The tool even corrects the camera and can do other things (that I sadly don't understand, since it's japanese language).
I rerendered the video with the corrected motion but left the sex scenes as is.
Thank you to the kind stranger, that showed the tool to me after uploading :D
::EDIT::I haven't posted in so long, I almost feel bad xD.
Kinda proud of this one, managed to add a few sex scenes.
Also, blender rendering is nice.Advice for improvements are welcome.
[Credits]
Girl Model: Uruha Rushia (潤羽るしあ) by たららたらこ (TararaTarako)
Man Model: Sin Sack 2021 by Ademar440
Stage: MMD Art Clubroom Stage by Maddoktor2
Motion: Pink Cat by アガちん
Camera: ピンクキャットカメラ by Marusu
Sex Motion: Pink Cat _ Motion.zip by tyron82