It is early Saturday morning and a roomful of bookish adults is contemplating sex. The NSW Writers Centre in Balmain is holding a day-long workshop in Writing Sizzling Sex Scenes. Fantasy and romance author Nicole Murphy is leading a class of published or would-be writers, all of whom are hoping to get great sex on the page.

”Build the tension and anticipation – foreplay for the reader,” Murphy tells the class. ”Slow down; let the reader experience things as the characters are experiencing them.”

”If you want to arouse the reader,” begins some especially memorable advice, ”you need to allow yourself to be aroused while writing it.”

And don’t hold back. ”Pretend your mother will never read it.”

When writers approach sex, holding back seems to be less of an issue than getting carried away. As a story takes a turn for the horizontal, even great authors fondle flowery adjectives or grope for cliches. They get bogged down in dubious metaphors – geological imagery abounds – or tedious descriptions of what bits are doing what in where. Sentences stop and start as if to emulate pelvic thrusts or else spill and gush in an unseemly manner.

In his novel Ed King, David Guterson manages ”massaged”, ”kneaded”, ”stretched”, ”rubbed”, ”pinched”, ”flicked”, ”feathered”, ”licked”, ”kissed” and ”bit” in a single sentence. Most sex writing is a massive turn-off.

”As writers, we want everything to sound as beautiful and interesting as possible, but sometimes we let our cleverness get away with us,” Murphy says, though the cleverness of the terms ‘front parlour’ and ‘back door’ (Guterson again) might not be immediately apparent.

Egregious sex writing is so rife it has inspired its own book prize. Britain’s Literary Review has awarded the Bad Sex in Fiction Award since 1993. Winners include, yes, Guterson, as well as Sebastian Faulks, A.A. Gill, Melvyn Bragg and Bridget Jones author Helen Fielding, who was sufficiently embarrassed to swear off writing about sex entirely.

Christos Tsolkas’s Dead Europe was shortlisted for the award in 2011 – “I was immersed in the slush of her moist meat” being one of the less unprintable sentences in the nominated passage. (Arguably, Tsolkas’s balls-and-all bluntness, even his use of that abhorred adjective ‘moist’, is in keeping with the characters in his books. Think how weird it would be if he lapsed into winking Edwardian euphemisms instead.)

As well as regularly defying good taste with their purple-headed prose, those writing about sex often stretch the boundaries of credibility.

In The Humbling, Philip Roth has his depressed, ageing protagonist seduce a lesbian, while in a dizzyingly implausible act of choreography, characters in Johanna Lindsey’s Savage Thunder make love while riding a horse.

But few books have forced quite so many readers to suspend their disbelief as E.L. James’s sadomasochism fairytale Fifty Shades of Grey. Whatever its other offences, the book continually flops when it comes to convincingly portraying sex.

”When Christian Grey makes Anastasia orgasm in minutes by playing with her nipples – and she a woman who has never had sex of any kind, including pleasuring herself – that’s high up there on the failure to know the mechanics of sex,” says the editor and author of the Marketplace series of erotic novels, Laura Antoniou.

As well as writing sex that culminates in believable orgasm (or not, as the case may be), any writer straying into their narrative’s erogenous zones needs to study sex, Antoniou says. ”Would you write an elaborate formal dinner scene knowing nothing about food? You need to know the proper terms for body parts and actions, you need to know how the human sexual response system works. I have returned so many stories full of editorial comments because the author didn’t know the mechanics of basic sex, let alone the esoteric, kinky stuff.”

Most importantly, good sex in fiction ought to be about something other than just the sex. (Some may chortle that no such requirement exists for real-life sex.) The act itself is less important than advancing the plot or revealing character. ”Sex,” as Anaïs Nin wrote in her diary, ”must be mixed with tears, laughter, words, promises, scenes, jealousy, envy, all the spices of fear, foreign travel, new faces, novels, stories, dreams, fantasies, music, dancing, opium, wine.”

Nin’s tales of sexual awakening are deeply sensuous – all veiled lamps, scented air and muffled caresses – whereas Ian McEwan probes the minds of his copulating characters, especially when his male protagonists try to distract themselves from climax (Atonement has Robbie pondering the colour black; Edward in On Chesil Beach turns to politics). Jonathan Franzen uses sex to plumb new lows of misery and pathos (Chip in The Corrections endures ”a night of anxiety and effortful concentration, punctuated by little stabs of throttled pleasure”), while Neil Gaiman’s American Gods has a woman terrifyingly slurp an unsuspecting man whole into her vagina by page 32.

In film, too, there are many ways a sex scene can serve the story: as romantic ecstasy (Titanic), as rite of passage (Y Tu Mama Tambien) or as prelude to murder (Basic Instinct). Cinematic sex can also be uniquely creepy (the sinister orgy of Eyes Wide Shut) or shockingly funny (marionette sex in Team America: World Police).

Some of the most memorable sex scenes exploit the storytelling possibilities of the medium, as with the bedroom scenes in Steven Soderbergh’s Out of Sight and Nicolas Roeg’s Don’t Look Now, which are intercut with what happened before and afterwards.

On the page, though, a lot of the more successful sex writing focuses on unsuccessful sex rather than the sizzling sort. Actor Brendan Cowell began his debut novel, How It Feels, with his virginal teenage protagonist ”trying to unlock a Target sports bra”.

An effective sex scene, Cowell says, is like any effective scene: ”It has to be true, it has to be compelling, and it has to involve conflict”.

”I was so frightened of sex in high school,” he says. ”The advice I was issued by my more experienced friends was so weird and misleading the whole event blew out of proportion. In How It Feels I wanted to draw a young man who finds the whole thing too intense, too real, too epic. Not only would this offer an antidote to the all-too-keen young male protagonists we are so used to, but the small, seemingly lost incident could go on to haunt him for the rest of his life.”

There is plenty of potential for humour, too, especially in the hands of cunning linguists alert to the juicy vocabulary of jiggery-pokery. Daniel Handler, better known in the children’s books section as Lemony Snicket, is characteristically wordy in his adult novel Watch Your Mouth: ”All the prepositions were in use: on, in, out, along, around, amongst.” Nicholson Baker’s House of Holes on the other hand is a full-blown pornographic wonderland, the home of such fantastically filthy characters as the clit burglar and a lake-dwelling creature called the Cock Ness Monster.

Sydney comedy readings night Erotic Fan Fiction embraces the inherent hilarity of sex with open legs, inviting writers to dream up unlikely celebrity shagging scenarios. Cowell himself penned a piece that involved the entire Aussie cricket team, First Tuesday Book Club hostess Jennifer Byrne imagined Paul Keating and Germaine Greer in a meeting of much more than the minds, and EFF co-founder Eddie Sharp took on Margaret and David from At the Movies.

Even in this format there’s much more going on than just the inappropriate bumping of uglies. “Playwright Lally Katz wrote one about Jennifer Aniston masturbating alone while googling ‘Brangelina’,” says Sharp. “Which isn’t really funny but simply devastating.

”The trick is writing about something you truly love and not holding back on the descriptive sex,” Sharp says. ”People appreciate the details.”

In January, the Opera House presented its own sexy readings event, My First Time. Since 1996, myfirsttime.com has collected anonymous first-person accounts of what D.H. Lawrence called the ”tormented tangle”: losing one’s virginity. The stage show is a carefully edited medley of the best of the 50,000-plus stories submitted by ex-virgins to the site over the years – sex on a plane, sex in a Burger King restroom, sex “in Mom’s minivan” and many more.

Compared with the tendencies of Guterson or Tsiolkas, most of the stories on the site are refreshingly free of grammatical, let alone literary, aspirations. “My brain said no, but my dick said yes” is about the closest the site gets to the gentle poetry of Anaïs Nin. That said, people are being drawn to these unflowery deflowering stories, whether online or onstage.

They come ”either to boast or to commiserate”, says creator Peter Foldy, ”depending on the success of their first time. From the tremendous traffic the site continues to generate I would say there is a definite titillation factor, too. Not sure too many people are going there for sociological research.”

With their naughty babysitters or knickerless French teachers, many contributions to the site are obviously straight out of the musty porn theatre of adolescent imagination, rather than lived experience. But some are too painfully honest and confessional to be made up. Even here, the most effective sex stories are the ones that go deeper, so to speak.

Despite its primitive interface and dud entries, the site has evolved into a vast online repository of coming-of-age experiences and the emotions attached to them.

It is more difficult to justify the existence of so much dodgy sex writing sullying our book shelves or smearing our eReaders. Unless you are E.L. James, plunging into a sex scene at every available opportunity is probably not absolutely necessary.

In Lolita, Humbert Humbert’s crescendo of trembling, lustful words evaporates just as he is poised to conquer his nymphet. Having piled on the narrative anticipation, Nabokov instead paints a succession of fleeting images and colours that have far more suggestive power than any physical description. As Humbert drily notes, ”Anybody can imagine those elements of animality.”

Sometimes the best option, for everyone concerned, is abstinence.

This piece originally appeared in Spectrum, the Sydney Morning Herald, as Fantasy fiction, in Dec 2012.