Let's face it, guys: writing sex scenes is hard. I'd go so far as to say that for many people, sex scenes are the most difficult type of scene to write. Part of that is a sex scene is first and foremost an action scene, so you have to be aware of the timing and choreography the same way you would if you're writing a climactic scene in a thriller. To complicate things further, while the thriller writers have nearly infinite options for how their scene plays out, you guys have one, since obviously your scene ends in orgasm. And, just for good measure, the thiller writers have a wide assortment of guns, explosives and other incendiaries while you guys get about half a dozen words for genitalia. Ouch. Is it any wonder that so many people hate writing sex scenes?
So what can you do to make your sex scenes stand out? It's twofold.
Treat your sex scene like an action scene. Block out the choreography, making sure that everything you mention is possible. Keep an eye on where hands and arms are, making sure that you don't end up giving your hero three (or more!) hands. Make sure that the scene flows in a logical manner--does her bra somehow come off before her shirt? Do his pants come off twice?
Sometimes, even when the sex is fairly clear, I find that I need to chart things out. I'll make a flowchart, detailing exactly what happens when. Once it's written, I go back and list off all movements so I can look at them without being distracted by the story. This can be really useful, especially if you use sticky notes. If you decide that the scene needs revision, you can play musical notes until you have something that works.
Once you know what's happening when in your sex scene, you can start wondering how you're going to describe it. One of the biggest problems for sex scenes is that it's so easy for them to become repetitive or mechanical--the same words or actions are used over and over, in book after book.
Some authors try to avoid this by using euphemisms whenever possible. "His throbbing trouser snake nudged against her labia, then slipped into her wet grotto." Ew. Especially in erotic romace, euphemisms are a bad idea. We might be able to skim past a few, but multiple euphemisms will trip up the reader--not only do we get sucked out of the story to wonder why you made that particular comparison (how is his penis like a ferret, again?) but repeated use of euphemisms makes your hero and heroine seem immature. If you can't say penis, should you really be having sex?
You also want to avoid Tab-A Slot-B sex scenes, scenes where the hero and heroine are clearly supposed to have sex, so they do. This is maybe the most common problem I see in submissions. The story's fine, the story's okay...and then suddenly the hero and heroine have sex, realize they're in love, and go off to live happily ever. All well and good, and there's certainly never wrong with sex + love + HEA, but you have to support that in your writing. There's more to writing sex scenes than just the physical aspect of it, and if you miss the underlying connection, you might as well not have the sex scene in at all.
It's not enough to tell your reader that the hero put his long, hard cock into the heroine's eager cunt. They need to know what it felt like, physically and emotionally. The emotional aspects are almost more important than the physical aspects, to be honest. These sex scenes are supposed to actively contribute to the development of the relationship, and you need to show us that. Tell us how the characters feel, what they're thinking. Give us more to think about than how big his cock is--tell us how satisfying it is, how he knows how to use it, how it makes her heart skip a beat.
When writing a sex scene, do:
- Pay attention to the emotional as well as the physical aspects.
- Utilize all of the character's senses. How does it smell? What does the other person taste like?
- Use charts and careful rereading to make sure that no one develops a third arm mid-coitus.
- Remember that with strongly emotional writing, a plan-vanillia, missionary-position sex scene can be every bit as sexy and arousing as a menage a trois with double penetration and light BDSM.
- Show us, don't tell us--saying "his long, hard cock was supremely satisfying" isn't anywhere near as evocative as telling us about how she was desperate for his cock, how she loved the sensation.
- Act like you're afraid to use graphic words. This isn't second grade, and saying penis isn't going to get you benched for recess.
- Get so caught up in making the sex as extreme as possible that you lose sight of the story.
- Forget why they're having sex in the first place--presumably it's more than just being in the same place at the same time. It's because they find the other person attractive, or because they're falling in love, or because they were both lonely. Don't cheapen the relationship in the name of sex.