Is it about the sexes, or sex?
It's a ticklish subject. One group member asked, "Are we talking about the sex of a character, or characters having sex?" It was a fair question. We're talking about characters interacting with sex, the character-driven scenes which are about relationships as much as they are about intimate moments.
The best book I've found on this subject is The Joy of Writing Sex by Elizabeth Benedict. In her acknowledgements she, well, gushes about the joy of the assignment, to write about writing about sex:
In addition to being paid to read sexy books and think for long periods about nothing but sex, another perk of writing this book is that I always have something to talk about at dinner parties that everyone wants to weigh in on, which is more than can be said about writing a novel. I am certain that I will never have it so good, conversation-wise, as I did while writing this book.Benedict's book is a recommended text for my upcoming "Writing About Sex" seminar at the Iowa Summer Writing Festival, but I picked it up at Powell's iconic bookstore in Portland, in the summer of 2003 when I studied at the Tin House Writer's Workshop. Slim volume, worth owning — especially for the sly looks it can draw at the coffeehouse while you read it. Everybody's interested in the subject. That's why the writing about sex is so essential to knowing your story through the hearts of your characters.