That's what I find disturbing behind the response. You'd think perverts would have a better appreciation for the fact that sexuality is diverse and not everyone experiences their sexuality in the same way. No sex-positive instructor should be pressuring a student into an act they feel uncomfortable with, even if it's a private act that almost everyone does, like masturbation.
It seems to me that one of the worst things someone who's in favor of sexual freedom can do is try to impose a normative straitjacket on someone else's sexuality. I've had people telling me that I didn't really know my sexuality, that my attraction to men was a result of psychological problems or my submissive desires were a result of abuse (never mind that I've never been abused; clearly I must be repressing it!). If only I could be instructed in the proper way of expressing my sexuality, I would be cured. I can't really read anything different into the treatment of this woman.
If it's okay for an instructor to pressure a student to masturbate because it's normal to do so and nearly everyone does it, that erases the ability for someone's individual sexuality to be taken seriously. It's essentially saying that because her sexuality isn't normal, it's okay to pressure her into things she's not comfortable with. Fuck that shit.
EDIT: Gonna try this one again, because I don't think I articulated it very well above. The above- that is to say, it's reasonable for a teacher in sexuality to require his students masturbate but not to "get a midget a donkey and about 6 feet worth of water hose," is based on a privileging of normal sexualities. It's okay to require one kind of sex act, because almost everyone does it, but not okay to require another, because almost everyone doesn't. More importantly, it's based on an idea of a single reasonable sexuality, or at the least, of certain acts that it's reasonable to want to do and certain acts that it's unreasonable to resist. So the revulsion that a normal person feels when they contemplate beastiality is a-okay and should be respected, while her reasons for not wanting to masturbate, whatever they are, are necessarily invalid. I think this delegitimization of reasons or wanting or not wanting to do a sex act is really problematic, and one behind a ton of the oppression sexual minorities face.
