It's every writer's nightmare. You've invested years of blood, sweat and, in my case, HB pencils in the library to construct your tale of deep passion and pent-up desire and now -- at last -- your central characters are edging towards the bedroom. At which point you start to suffer from writer's droop. How are you going to encapsulate the earth-moving wonder, the erotic arousal and tender protectiveness of the longed-for moment?
Imagine this and multiply it by 10 when the main character of your novel, The Lady and The Poet, happens to be John Donne, perhaps the greatest erotic love poet in the English language, whose poetry glitters with clever seductiveness, carnal longing and a subversive delight in sex?
Add to the problem the helpful advice from my agent that when Donne and the young woman with whom he falls passionately in love, Ann More, finally make it to the four-poster -- "it had better be good!''
At this point not just writer's block but paralysis sets in. Clearly, in order not to produce something utterly trite or unbelievably naff, I had better see how other, greater writers than me had coped. Lady Chatterley's Lover was an obvious place to start.
I have to confess to a certain soft spot for DH Lawrence with all that "thee" and "tha" and "ter'', and 19 words for the female equipment and even more for the male. Now I like a bit of primordial thrusting, but Lawrence's obsession with roots (not of the vegetable kind) and globe-full breasts does make me giggle rather than feel moved, especially when I recall Sean Bean's accent as Mellors the gamekeeper in the television version.
Fanny Hill was also in the running because it is billed as "a classic of erotica''. Yet I found its endless scenes of "pleasurings" as Fanny progresses from country innocent to knowing courtesan, were actually ones for the gentlemen. Not surprising, perhaps, since it was written by one.
Moving swiftly on, two of the most celebrated modern sexual encounters are Ian McEwan's Atonement and Birdsong by Sebastian Faulks. Eagerly I re-read Atonement and found it scored highly on erotic build-up, both physical and emotional, and wonderfully captured the self-destructive inevitability of desire, but when I got to the famous scene in the library, it struck me as moving rather than erotic.
The sex scenes in Birdsong seem to divide people. One friend declared them "the most beautiful in the English language" -- yet when I bought the book for this article, my local bookseller insisted that the sex was "the worst bit of the book", and that Faulks should have stayed in the trenches where he excelled.
By now, though, I was beginning to learn a few lessons, the first of which is that being convincingly erotic is hideously difficult. It seems the writer can be erotic or convincing, but rarely both at the same time. For this, blame sex itself. The awkward truth is that real sex is often anything but erotic. It is awkward, kinky, funny, tender and messy.
One thing I learned fascinated me. Whenever the topic of sex scenes comes up everyone nominates Don't Look Now, by which they mean the film version with Donald Sutherland and Julie Christie, which spawned the great and long-running "Were They Actually Doing It?" debate.
So how did Daphne du Maurier, the author of the short story on which the film was based, manage to write perhaps the most erotic scene in literary history? With trembling fingers, I opened the collection of stories only to find that it consists of four lines, none of which is faintly titillating!
The graphic yet tender scene was the sudden inspiration of the film's director, Nick Roeg, who thought the couple were quarrelling too much and instructed them spontaneously to improvise an erotic encounter.
And just to underline how tricky such writing can be, while Birdsong may have turned some people on, another of Faulks' novels, Charlotte Gray, landed him an honour we poor writers dread -- being nominated for the Literary Review's annual Bad Sex in Fiction Award. There is even a ghastly ceremony where you are presented with the prize.
And yet, anyone who does win this unflattering gong are in august company: Paul Theroux, Salman Rushdie, Tom Wolfe, Melvyn Bragg, John Updike and Gabriel Garcia Marquez.
So what's a poor novelist to do? Part of the challenge is the linguistic one. Do you call a spade a spade or risk ridicule by getting all metaphorical? And language itself has fashions. In the era of the bonkbuster the word "shaft" became wildly popular with lady novelists of an erotic bent. Other writers prefer the symbolic. Lawrence was particularly keen on dark waves rising, not to mention heaving swells, plunging deeps and the occasional dark, dumb mass.
A few clever novelists even manage to evoke thrills through humour. Take the witty seductiveness of Cold Comfort Farm when the sukebind is hanging heavy on the bough -- leading to all sorts of unsuitable shenanigans in the hedgerows between sexy Seth and Meriam, the hired girl.
But this was not going to help me in a novel about grand passion where John and Ann are risking everything for love: ignominy, loss of social position, family rejection, even the weight of the law since Donne was thrown into the Fleet prison as a result of his secret marriage to Ann.
And there I was, stuck again. And then something rather unexpected happened. I was resentfully driving my teenage son somewhere or other when he replaced my soothing classical music with his latest musical acquisition. In the manner of teenage boys he played the track not once, but over and over and over again.
And then I started listening. It was a track called Bones by his favourite band of the moment, The Killers. Something about feeling my bones on your bones, and my skin on your skin. Now as it happens, bones are a rather Donnean obsession and, sitting in the car, I had a sudden inspiration and ran up to my study to write one of the book's love scenes.
I have no idea if it is erotic. The best a writer can do is create a mood, a charged moment, and hope. Only time will tell whether readers find it tender and passionate or I end up in the Bad Sex Awards. I will say one thing for it. It's short. If I've learned anything from trawling through other people's sexual expositions, it's that, like sex in middle age, no matter how much you love each other, it's better not to go on and on.
The Lady and the Poet by Maeve Haran (Pan Books)