Actually, I think they're all quite good. Descriptions of sex don't start from zero, so reading any of these without a run-up is likely to produce a wtf reaction. For any scene to work, you need to know the background of the characters, what they want, what they're afraid of, what they think of the other person, animal, vegetable or fruit in the scene. Given that there's probably some reason in the original for the narrator or viewpoint of the book to portray the couple this way, this description by Nick Cave (yes, that Nick Cave) is pretty evocative: "Bunny lies on his back on the sofa. He is naked and his clothes sit in sad, little heaps on the living room floor..."
Anyway, what I wanted to talk about was this comment from Lucasta Miller:
Booker Prize judge Lucasta Miller says sex has been at the centre of most of Western literature for centuries but too much of it nowadays reads like a "biology textbook".
"A trap people fall into is an earnest anatomical description of sex. The difficulty with the anatomical is that it can read like a bit of a textbook.
"To stop it doing so, they will put in flowery metaphors from the animal kingdom, but you don't need that detail.
They put in flowery metaphors? From the animal kingdom?
Someone needs to work on their metaphors, and it isn't Nick Cave.
Read the shortlisted passages at Literary Review here.