It is crazy, just the lengths that you have to go for the first H scene with minerva not to sound like a rapist wetdream, and for the lines to still check out.
Cuz no matter what you do, the script will still assume "something" happened, even if you quit immediately. And god forbid you did more.
If you cum (anywhere), she swears very angrily she'll "never forgive you".
Which is fair for a first time (especially with no "give underwear back" path), so one could call it a day earlier.
But just about everything else is lame too.
If you dick her (even if you go at it for good, with her finally enjoying it for once) she is pissed that you were rough.
If you only stick the wand in her and stop there.. she's somehow pissed because you technically left her blue-balled?
If you remove her clothes and/or panties she's in various states of disappointment, outrage, scolding or sadness.
You can still jerk off at that point, but that's simply the most miserable thing of course (even more so with this eery inexplicable force that seems to have her petrified like at gun point).
So, the best case scenario is really just to fix the dress (and please, do, otherwise she treats you like you had tried to pull it up) and exit. She will still half-heartedly "joke" with a cringed expression that next time you should listen more to her wishes, or not take her hostage but better than incel I guess (maybe you can still grope and flash her, to somewhat justify this attitude, but don't switch to the "angry talk" mode).
EDIT: lol, unbelievably this gets even worse in chapter 4 (right when you start to think the extreme puerileness of the scene might have been on purpose).
Now it's McGonagall that wants to fuck you dearly, but you are only given two equally offputting choices: either yield and somehow you have to experience again the same exact scene of the prologue (now in an even more nonsensical context), or not only you turn down humping a sexy MILF but you even mock her for not being a teen.