The woman is Belle de Jour, author of Playing the Game, and her suggestions pretty much read like pointers for good writing in general. She says,
Arms are flying, tongues are flicking, and where on earth did that extra arm come from? The effectiveness of sex writing depends, as with real sex, on getting from point A to point Z via all the letters in between. Too many stories start on the sofa, then segue straight into a threesome on the beach.
Plenty of non-erotic books fail because the author can't keep track of the rooms in a house or the stops on a bus route, or because the action moves implausibly quickly or slowly. Getting from A to Z effectively: good advice for any writer. So is de Jour's caution not "to dwell on what ruffly garment was worn, the precise glossy shade of a woman's hair, and so on," or to "describe anything that is not in fact chocolate as being 'like chocolate.'" Perhaps her only totally sex-specific tip is this one:
If I wanted to read about the kind of sex I have every day, I would . . . well, I wouldn't. Why fantasise about what you already experience? I go to the written word for places and faces that I don't get at home. Hot people in hot climates. Sex acts I can hardly imagine. Porn is about the unachievable . . . and, therefore, the inherently desirable.
The male sex-tipster, Ewan Morrison, starts off by explaining why women don't write about sex as well as men do (heard this before?). He says, "it's because male writers have a much longer tradition of breaking taboos about sex (straight and gay)." His examples are Henry Miller and Anais Nin. He writes,
Miller is all vigour, urgency and detail. Nin's body becomes relatively anonymous for him. Nin has to make the act seem poetic and address the virility of Miller's 'authorship.' 'His book swells inside of me,' she writes. His penis is, almost literally, the canon of Western male fiction.
Comparing a dick to a book (kinda oblong) doesn't sound all that hot, but is anonymity really the recipe for great erotica? Morrison seems to think so. He writes that,
the bourgeois distinction between erotica and porn [...] is based on an opposition between ethically good sex with 'wholesome, well-rounded characters' (erotica) and nasty cheap sex with anonymous bodies (porn). Porn is omnipresent now and calling a certain kind of porn 'erotica' is a middle-class attempt to set itself against the tasteless culture of the masses.
It's clear here that we're supposed to think sex with "wholesome, well-rounded characters" is less fun than "sex with anonymous bodies." And it sure is, if you make those characters sound like big balls of oatmeal. If, however, a character has an interesting personality or an exciting (or twisted) relationship to the person he's fucking, isn't that more arousing than anonymous tab-a-into-slot-b? Maybe not for Morrison, who seems to take a pretty narrow view of what's acceptable in erotica. He says,
Write from experience, not fantasy[.] Fantastical sex scenes are hilarious, shallow and awful. Follow the masters: Miller, Jean Genet and Nin, who wrote from the depths of lives devoted to sensual pleasure. If you don't have the experiences to enrich your writing, go out and get them or stop trying to write sex scenes.
Pretty much the polar opposite of Belle de Jour's advice, and kind of odd coming from someone who wrote Ménage, a novel inspired by the ménage à trois between Henry Miller, June Miller and Anaïs Nin. Presumably Morrison never actually had sex with any of these people, and thus his writing didn't really come from experience. Perhaps he discovered that imagining sex you could never or would never have is actually titillating? But then again, that's probably just my failure to break taboos talking. Better go back to fucking books.