All right, maybe not exactly. But I write about them the same way. I got a funny look from someone the other day when I said that, so I'm going to explain the similarities.
First -- non-sex related unless you have different tastes than me, but who knows *grin* -- and this applies to sword fights or just describing warriors and knights in general, don't get tied up in what I once saw an editor call "weapon porn". I am a heck of a lot more interested in what the armour and weapons are called than 99% of my readers. I know the name, weight and capabilities of every piece. So should you, but don't necessarily list it. They really just want to see what it does, not hear its name. But do get the capabilities of the weapons right, please. Please. Swords did not weight 30 pounds, and it was not a matter of the heavier the better. Most weigh less than 3 pounds. 6 pounds is about tops for a functional sword that is not for ceremonial use only.
Swords cut. They do not crush.
Know all that to make the scene authentic but don't burble it all out and bore your poor reader to death--or on to another novel.
(Possibly that is more like a sex scene than I thought. Don't list all the body parts either!)
Now on to the sex part:
1. The senses do not stop working during battle or during sex. Battle is noisy and smelly. Things touch; things taste. The coppery taste of blood in your mouth. The tickle or sting of sweat trickling down your sides. The shit from dead horses and men. The senses put the reader there in either type of scene. Don't leave them out.
3. Battle and sex are both drippy. There are a lot of fluids. Blood in the mouth, on your hands, in your face. Sweat dripping. Horses lather and bleed. Mud squelches under your feet. Important stuff. I'll leave the sex dripping to you. *grin*
4. Don't announce orgasms OR winning the battle. In a battle, no one holds up a sign and shouts, "it's all over". Battles take a long time, sometimes all day, and even when you've won, the fighting rarely stops with that. There are enemies to be hunted down or an escape to be made. Or you're a prisoner wondering who of your friends survived. From your spot in the battle, you may not even know whether you've won or lost. There's a good chance you won't just like you don't necessarily know... *chuckles*
5. It is ALL in the feelings. Exactly where you put the feet or how the sword was swung doesn't mean a thing any more than how "Part A goes into Slot B". What matters are the emotions and reactions. There can be all kinds of feeling in battle. Cool calculation as you figure out how the enemy will react to what you do. Or you might be totally lost in the moment, seeing nothing but the next swing of the sword and the next victim ridden down. It may be fear and terror. It may be elation. But it is the feelings that count! If you don't know that about sex... well, I don't know what to tell you.
6. You had better feel it yourself. You notice I describe it as though it is happening to you. If your sex scenes don't arouse you, they probably have a problem. If you don't feel your own battle scenes, then you probably need to get more inside your character.
So that's why I think they're the same. Kind of. But I do try to be alive and unbloodied after sex. My characters can't necessarily say the same after battle, because I try to always have them at risk. And that's another essential point. If there is no risk to your characters, is there really any point in writing the scene? Just another thing to think about.
My own novel, Freedom's Sword, is based on the life of Scotland's hero, Andrew de Moray. You can find it at Amazon, Barnes & Noble and Smashwords.