It already exists. This can only be done by randomized NPCs who have a high vulgarity... Actually, what else can you expect from them in a simplified character system? Also, even with this in mind, they won't do it if your character has enough relationship points with her - 100.
Anyway, if you have any problems with this, you can make randomized NPCs less vulgar using the point generation function. They do this with a vulgarity above 90, which already a priori has a small proportion of RNPCs in normal generation conditions.