It's the most natural thing in the world. We like to have as much of it as possible and while sometimes disappointing when it's good it's the most amazing experience imaginable. Everybody is talking about it - so why is writing about it so hard and why are there so many bad sex scenes written?
You can never really know someone until you sleep with them. Sometimes not even then. Writing anything can be a pretty exposing experience and getting over that fear is one of the first hurdles a writer must deal with. Some writers never do. Even if we invent characters a million miles from ourselves in story-lines we could never hope (or want) to experience, our sense of self imbues our characters and our stories. Our world views and sensibilities pervade even our least autobiographical work. Perhaps only we can tell, and perhaps we don't like to admit it, but we always give a little of ourselves away whenever we write anything.
So how can we write about something that the whole world may read when we struggle to discuss it with the people we feel closest to? How can we write about a character's deepest desires when we can't even talk about our own. And what if mum reads it?
Write what you know
If you can't stand it, are not very good at it, or have never done it then the chances are you're not going to be very good at writing about it. This more than anything else. I've never been hang gliding but I'm fairly sure with some online research and a little imagination I could write convincingly about it. Not sure I could do the same about sex if I'd never had it (and I have - honest).
This is because sex is such a deeply personal and intimate experience - it can be tied up with powerful and contrary emotions: love and jealousy, confidence and shame; both empowering and belittling - and sexual desire can take us to places within ourselves we didn't even know existed, and make us do things we wouldn't normally dream of doing.
We give our characters authenticity by lending a piece of ourselves to them. We think 'what would I do if I was this character in this situation?' We look for empathic emotions and feelings within ourselves to project into our characters, and curiously, it's that look inside ourselves that creates universality in our characters – that 'I feel that too and am not alone' response from our readers. It's that personal projection into another character's sexual psyche that makes literary sex hard to write – but only if we're scared.
Keep it real
Once you get over fear, prudishness and self-consciousness writing a sex scene should be like writing any other scene – you must ask yourself what the purpose of the scene is. Is it to reveal character? Is the scene there to progress story? Have the lovers finally come together after a novel's worth of prevarication? Are they the right or wrong pair? For these kind of scenes explicitness is not always required. Ask yourself if the reader just needs to know it happened, or if they also need to know how it was when it happened. Was it the best sex in the world? Was it a disaster? Who had the most fun? If the story demands those kind of answers then you'll need to take it into the bedroom.
You also need to know what response you want from your reader. Satisfaction? Frustration? Laughter? Titillation? You have to know what it is you are trying to achieve if you ever hope to. There are enough literary sex scenes that are so bad Literary Review magazine can have an annual 'Bad Sex in Fiction Award'. Most of the winning passages use horrendously distancing language which only demonstrates that the otherwise accomplished writer is afraid to engage with his subject matter. There's also the other kind of authorly distancing – clichéd language that produces decidedly cheesy sex scenes – calloused hands traversing creamy-white thighs etc. If you keep your distance like that you're going to keep your readers at a distance and you might end up winning the wrong kind of award. If you want to write a convincing (and sexy) sex scene, then you're going to have to do what you should be doing for all your scenes, asking yourself how your characters would really feel and desire in that situation – and the best way of knowing that is to project yourself into those characters. You might learn something about yourself too. You'll certainly write better sex.
And of course you'll need to do frequent, in-depth and physical research...