I heard this joke from my mother, when I was about 11 or 12.
Two nuns were walking through the woods when they were set upon and raped. One said to the other, 'Whatever shall we tell Mother Superior?' The second replied, 'We'll just have to tell her that while we were walking through the woods, we were set upon and raped twice.' The first one said, 'Why twice?' The second replied, 'We still have to walk back through the woods again.'
By the logic of this joke, women, however uninterested in sex they may appear to be, are desperate for sex and simply dare not admit it. Therefore, the man who gives them sex despite their apparent objections is doing them a favour. Rape is just a form of sex, and women enjoy it enough to hope it happens to them again.
Jokes like this one reinforce the idea that when a woman says 'no', she really means 'yes', that reluctance is nothing more than a pose women adopt, that there is no meaningful distinction between sex and rape, that rape doesn't really do any harm. And jokes like this one get told all the time, not behind closed doors, but proudly, out in public.
That's the kind of thing we mean when we talk about rape culture.
Just in case you weren't sure what it meant.
Also, Ampersand has compiled a list that's a good ostensive definition of male privilege.
And, this isn't entirely relevant, but Echidne comments on Katha Pollitt on Maureen Dowd.