I am a big advocate of using "cunt" to describe ladyparts and not ever, ever as an insult. I think it's a sexy word. I think it should be used more often to take the stigma away. (Of course, I'm a bit hypocritical because I don't like any of the other words you've listed, like "pussy" and "twat," which I also think should not be used as insults.)

Though of course it depends on the narrator, and in practice I probably use other euphemisms more often, or just the tried-and-true "inside."

Icon very related ;)