...The Shape of Her by Rowan Somerville. Here's an excerpt:
He caught her rhythm, pulling and releasing, cradling and crushing; pushing up through his fingers with each swing, mining up, like an otter through wet sand. Her sounds shifted from moans to grunts, insistent, almost desperate cries from the throat … 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 in the night. He took it between his lips and sucked the salt from her. He hooked his fingers into her waistband, caught the elastic of her underwear and began pulling down. The knot on her light cotton trousers held fast as the fabric reached the curve of her backside. She twisted from him and stepped back.
The books that Somerville bested (including Jonathan Franzen!) are here. You can read more bad sex scenes from The Shape of Her at The Guardian. They also raise a great question: Why is there not a good sex in fiction award? Rather than just snickering at embarrassing efforts, it seems as though sexy, literate love scenes should be rewarded, too.