There's a weakness she has that can stack, so take full advantage of it. You'll need items for it (I don't THINK you can do it normally except in deep kiss mode) but the items will stack every time you do it. Last time I beat her was because at the end of the round she'd get 800 arousal thanks to the stacking of said weakness. (Sorry, I'm a little loopy thanks to allergies, but hope you get the idea)
I beat the boss, but without using said weakness and having only 40 on every skill.
although it took me three tries and like probably 20+ total climaxes on myself.
how did it go for you guys?
also for the people actually needing help with the boss just try taking a chill pill
and go fight her
a good tip btw is getting veneficia's love chocolate which gives you an extra climax