Game initiates penetration when penetrator is near hole entrance.
Exact penetration is visible: tip aligns, looking directly inside hole.
There is a delay between entrance touch and penetration start.
That delay depends on "tightness" personality trait, and looks like it simulate "how difficult is it to slide into the hole".
Additionally, there are two appearance traits:
- initial hole depth: limits penetration depth
- initial hole width: limits max penetration speed
All of them can be loosen in process, but if initial values are bad, they are bad.
Mouth works slightly differently, because it generally requires to open mouth, which requires some consent.
So, to penetrate hole, you need place proper tool as close as possible to hole entrance, and wait until it "penetrates".
And fight evasive maneuvers
Because, unfortunately, game does not track genes, it tracks models, and it "breed" models.
And when it breeds them, it compare model pairs using gene rating.
If you do not carefully rate each model, or rate partially,
some genes will degrade to randoms.
When appearance (especially facial group) degrade to random, you get creepy monsters, because some genes are more important than others.
That's why you cannot rate just boobs(or something else), because without guidance (both models rated 0)
game will shift unrated genes to random values.
Italic words are speculation, because I think there was some work with genetics after 9.1, and that may be not true.