So now the illustrious Kelly Hunter joins us (yay Kelly!) and says this...
(I don't know if quoting from the comments is the done thing blog-wise but TOUGH - it means you don't have to open another window and I am lazy and besides, what she says is important!):
What really makes a sex scene sing for me is when I have an emotional connection with the characters the author has built. Where are they emotionally before they move into the scene? How do they react coming out of it...? Don't forget that it's just as important for the characters (and the reader) to experience the aftermath of a sex scene as it is for them to experience the sex scene itself. Who's in denial? Who knows they've met 'the one'? Who retreats? Who wants more? Who tries to control it? And how does this change the story? A sex scene is a turning point. A writing tool if you like. Position it for maximum impact. As for the sex scene itself, I'm a firm believer that it's the author's job to sucker me, the reader, into that scene boots n all, right from the go get. I don't care how you engage me; with humour or with snark, naughtiness or a fun premise, sensuality or sadness, just give me something to connect to on an emotional level. Because if you don't I'm going to skip that scene and pick up the story again after it's all over. Tab A into slot B stuff doesn't interest me. Emotions do.
Perfect. And she's so right re the immediate aftermath - that's just as important as the actual bit if not more so. And it can be so hard to get right (thinking of WIP as I write) - especially if the sex scene is early on. Lemme tellya, the immediate aftermath in Wife for a Week is a horrible wee misunderstanding of intention that leaves both characters feeling pretty ratshit - its good stuff!
And yep, the emotional drive is the key. Again I think this comes back to characters - if you're just describing what hand goes where you could be talking about any old Joe - it needs to be real for those individuals - they'll act or speak or think and feel in their unique way. If the reader is connected to them, then they can go with it. Otherwise it can get boring.
Ultimately the degree to which you describe is up to you.
Enough for now.
Meanwhile, my call story is up at the Pink Heart Society - come say hi!