The Bad Sex In Fiction Competition was inaugurated by the British Literary Review in 1993. According to its Web site:
The Literary Review Bad Sex in Fiction Award was inaugurated by Auberon Waugh in 1993 to 'draw attention to the crude, tasteless, often perfunctory use of redundant passages of sexual description in the modern novel, and to discourage it'. The prize is not intended to cover pornographic or expressly erotic literature, and is limited to the literary novel.
The nominees, and the passages for which they were nominated, can be read at the Web site. Scroll down that page to see the links.
The BBC reports:
Author Jonathan Littell has won the 17th annual Bad Sex In Fiction Award, for his novel The Kindly Ones.
The book, which was originally published in French, won the Prix Goncourt in 2006 and has sold over a million copies in Europe.
Judges at the Literary Review gave him the bad sex prize for a passage that begins: "This sex was watching at me, spying on me, like a Gorgon's head".
The award was accepted by Littell's agent. He has yet to comment.
In one excerpt, the author describes a sexual encounter as "a jolt that emptied my head like a spoon scraping the inside of a soft-boiled egg".
The Literary Review said Littell's book was "in part a work of genius", adding they hoped the author would take their dishonour "in good humour".
There's more at the link.
Reading those descriptions of sex, I'd say Mr. Littell is a worthy winner - but, on the basis of the available evidence, he might be a less-than-perfect lover!