What I did was cunt tease deny her (got rid of the dick, I'm a monster I know), then buttfuck, then cunt tease release. I read somewhere that having her cum from the cunt tease release is the only way to actually raise her obedience stat from an orgasm but I'm not sure about that.
You basically do the deny, buttfuck, release cycle constantly, keeping an eye on her appearance or the codex to see what her lust is at. Obviously her having an orgasm resets her lust. You can see her lust level in the codex under Log: Tavros. If it gets above 80 she'll masturbate and you'll need to punish her. This will also raise her obedience level. Whenever she has an orgasm you'll need to start the cycle over.
If you try to tease deny her when her appearance says that she is visibly pent up, you'll accidentally make her orgasm, lowering her obedience. If you try to tease her when your own lust is up, she'll make YOU cum and that will lower her obedience. If you try to punish her without actual cause, she won't react well no matter what stage of obedience she is in and will lower her obedience.
Basically, tease her then buttfuck her then give her release on repeat. Manage your own lust so she doesn't get the upper hand, punish her every time she masturbates without permission but not any other time.
Here's what caught me up: When she is at 80% obedience, in order to progress to where she is willingly your slut, you want to do the normal cycle EXCEPT THE RELEASE BIT. Normally you want to manage your lust to make sure it's low when you tease her but when you go to do the end tease release of the cycle, you need to have high lust. This will trigger the scene that transitions to her accepting and enjoying being your slave. Her obedience will stay at 80% (it wont go lower but it won't go higher either, its part of her character and honestly I like that), so you wont have to worry about that anymore.