Thanks for the detailed comments, guys. I read them all and these things help me determine the best way to do things.
It is interesting to note that in Honey Select there are mods that solve this problem. I've been doing some tests and it is possible to make penetrations much more realistic with some work. I still haven't found any mod like this for Koikatu. If one day someone creates it, it will be possible to apply "physics" to the girls' pussy, and from there the penetration scenes will be much more fun.
Unfortunately, the way Koikatu works is still based on "clipping". What I do is use camera angles and modify the model of the vagina to give the impression that there is some interaction, but there is no more detailed animation where the vagina actually interacts with the penis.I know is a kind of dumb question but does the dick clip through the pussy in the sex animations of this game? It just really bugs me in illusion games-based visual novels.
It is interesting to note that in Honey Select there are mods that solve this problem. I've been doing some tests and it is possible to make penetrations much more realistic with some work. I still haven't found any mod like this for Koikatu. If one day someone creates it, it will be possible to apply "physics" to the girls' pussy, and from there the penetration scenes will be much more fun.