You're hooked into reading this, aren't you? Few things are more fascinating than sex. Movies are full of it. Television is full of it. Books are full of it. Even the Bible is full of it.
So what has this got to do with writing? Everything, that's what. Even if you are writing a novel about a convent in the fifteenth century, sex will come up sooner or later. Especially if you are writing a novel about a convent in the fifteenth century. And for every character there is an unspoken or clearly obvious sexual point of view.
Explicit sexual scenes that would once have been considered pornographic are now commonplace in popular literature. I read a lot of thrillers and mysteries. Writers like Jonathan Kellerman and James Lee Burke are masters at creating steaming sexual scenes that reveal the inner depths of a character.
That's the key. Sexual scenes reveal, they're not there just to titillate the reader. If a sexual encounter doesn't deepen identification with your characters (it does usually take at least two), it doesn't belong in your story.
Okay, you've created the scene and it's the right place in the plot for it to happen. Good. Have you thought about the reader's point of view? If you are a man writing about sex, how do you think about it? If you want any loyal readers of the female persuasion, you'd better come up (pun intended) with something more than the typical masculine thinking about sex. Because, guys, (drum roll) women don't think about sex the way we do.
I refer you to any book by Diana Gabaldon, who has only sold about umpteen million copies of her fabulous Outlander series. Sex is one of the reasons, but not the only one. She took the classic historical bodice ripper into the stratosphere and blew away half a dozen genre barriers in the process. You want a female point of view about sex, study her work. She is pretty good at capturing the male viewpoint as well. Her sex scenes rock.
As a male writer, you can get away with only the male point of view, because everyone likes sex. But getting your reader to identify with the character while he/she is in the act is a different story. Can you engage your female readers in that way, if you have any? It ain't easy. The same is true for women who write, in reverse. Many sex scenes written by women tend to leave male readers yawning, if they somehow find themselves reading any book by a woman. Because (drum roll again) men don't think about sex the way women do.
Okay, so you all knew that. But maybe you forgot when you were writing that scene. Writing sexual scenes that feel authentic to both male and female readers requires understanding the difference in the way men and woman think about sex. As for me, I'm still working on it.
I challenge you to write a sexual scene from the feeling/physical/emotional point of view of each character. Run it by readers from both genders for an honest opinion. Prepare to be surprised.
Let me know how it works out.