A few years ago three friends and I were taking a cab ride. For some reason the conversation turned to fellatio, and went ribaldly along for a few minutes in that vein. Playing along, I mentioned something about cunnilingus. The reactions from those friends were striking. While they'd been happily discussing a woman pleasuring a man (moderately explicitly), the idea of a man enjoying pleasuring a woman in the same way was somehow disgusting to them, a topic never to be brought up in polite society.
I was reminded of this over the weekend when I happened to catch the close of a George Carlin (at least, I think that's who it was) stand-up set in which he read off a list of sexually explicit phrases.
Why did that remind me of that conversation in the car? Well, because a book a girl once urged me to read ("Box Lunch: A Layman's Guide to Cunnilingus") started out with an assertion (or at least I was told it did, I haven't actually got around to reading it yet (looked it up today, turns out it's only available at the reference library), sigh) that there were only a tiny number of ways to refer to cunnilingus compared to the number of words used for fellatio.
Carlin had quite a few references, but there were few that referred explicitly to the act of cunnilingus, as distinct from the labia. Which reminded me of the book, and it's (reported) assertion about our culture's squeamishness about the act (explaining the lack of words to describe it), and from there, the reactions of those friends in a cab (backing up that assertion).