"Like a lepidopterist mounting a tough-skinned insect with a too blunt pin he screwed himself into her". This year, the Literary Review's Bad Sex Award, set up in 1993 by Auberon Waugh to draw attention to the "crude, tasteless, and often perfunctory use of redundant passages of sexual description in contemporary novels, and to discourage it", was given to Irish novelist Rowan Somerville for The Shape of Her. Another scene goes like this: "He unbuttoned the front of her shirt and pulled it to the side so that her breast was uncovered, her nipple poking out, upturned like the nose of the loveliest nocturnal animal, sniffing the night. He took it between his lips and sucked the salt from her."

And it seems that not even the biggest superstars of contemporary fiction are immune from occasional lapses into purple prose. Salman Rushdie once wrote that "[Boonyi] pulled her phiran and shirt off over her head and stood before him naked except for the little pot of fire hanging low, below her belly, heating further what was already hot." Philip Roth, whose novels like Portnoy's Complaint and Sabbath's Theatre are amongst the horniest in the English language, wrote that "It was as if she were wearing a mask on her genitals, a weird totem mask, that made her into what she was not and was not supposed to be." In Jonathan Franzen's Freedom, a character's clitoris is described as a "protuding pencil of tenderness".

Negotiating the rocky path between ham-fisted metaphors and dull mechanics of the "he unbuttoned her top, she nibbled his ear" sort is certainly tricky. And the sniggering ridicule of those who judge - and comment on - the Bad Sex Award may well play some role in discouraging writers from writing about sex. Indeed, no less a writer than Martin Amis, whose debut The Rachel Papers revolves around a series of adolescent bedroom antics, recently said that writing about sex was practically impossible. "It's not that surprising," he said, "Of all human activities this is the one that peoples the world. With that tonnage of emotion on it, if there is going to be one thing you can't write about then that would be it. It's a bit like why it's so difficult to write about dreams."

Many readers feel that contemporary authors aren't taking the risks they should when writing about sex; the sort of risks which DH Lawrence took in Lady Chatterley's Lover. "She clung to him unconscious in passion," Lawrence wrote, "and he never quite slipped from her, and she felt the soft bud of him within her stirring, and strange rhythms flushing up into her with a strange rhythmic growing motion, swelling and swelling til it filled all her cleaving consciousness, and then began again the unspeakable motion that was not really motion, but pure deepening whirlpools of sensation swirling deeper and deeper through all her tissue and consciousness, til she was one perfect concentric fluid of feeling, and she lay there crying in unconscious inarticulate cries."

So, writing about something as profoundly personal as sex is difficult but doable. We invited Sarah Duncan, whose Kissing Mr Wrong has been longlisted for the Romantic Novel of the Year award, and Guardian journalist Susanna Rustin, to debate what they thought was the way to do it.