1
I'm trying to keep at least some logic in the game.
So, Katia won't strip naked without a reason.
But!
I'm working on a system of arousal and various sexual addictions the heroine can develop — and exhibitionism is one of them.
Over time, Katia will start wanting to get partially or fully naked.
2
Same goes for initiating sex.
To keep it short: yes, eventually the heroine will be able to initiate sex scenes herself.
At the later stages of certain addictions, she may even do it against her own will.
These high-level sexual urges can be suppressed using "Mind" points.