>>59027 (OP)
If you want to make something a little more unique, make sure that combat stats and ability are also part of her training, that she still need to win tournaments and some random battle as well, no need to code a combat system in, just and rng with threshold stats that guarantee victory if the value is high enough
The somewhat more unique part, would be that training her combat skill make her will stronger, making harder to train her slutty traits, not diminishing them, just make them harder to train, like a multiplier if you want to simplify the concept
The player can train her as it wish, but the need to balance out the combat part can make the game difficult enough to keep the player interested without turning it into a grind, not much at least, or a waiting game to unlock more skills and scenes, it would also require images of her doing something lecherous while training, you may need to commission them
This method would allow the player to train her vaginal skill even at the beginning, but it would penalize her will more, requiring more combat training to compensate and therefore, making her training a little harder, the player would need to choose carefully not the sexual training as much as her combat training to compensate and avoid turning her into a bimbo
What'0s the bait tough, why an already well accomplished and headstrong martial artist would accept to be trained this way? It need to be something she cannot just punch or kick to fix, and really believe that somehow obeying you is really the only way, or becoming a slut is necessary because...what?