There is, in some alternate universe, a sort of "sweet corruption" game in which the super-uptight Sandra is slowly brought out of her shell through the inexorable power of mind-bending sex...the only logical cure for OCD given the immutable laws of adult gaming. It doesn't start with her as a virgin and it doesn't end in gangbangs or slutification or anything like that (maybe the very occasional threesome, depending on how you play it), it's just about turning a sexually conservative girlfriend into a sexual dynamo while simultaneously convincing her that it's okay to wear clothing more than once. I'm picturing the first sex scene — third date, maybe — as absolutely-no-foreplay intercourse under the covers and in the dark. Proceed from there.
It would look a lot like a Haley-free version of this game, actually (or one in which Haley isn't so obviously the Designated Lust Object). Sandra deserves that game, especially given what this one's probably going to do to her. (Though I wouldn't be all that surprised if there's an MC/Sandra ending.)