|I don't know...maybe this IS sexy.|
In my view, a romance novel can make two mistakes in this arena. Sex Too Soon, as mentioned above, or it happens at the right time, but it's an Unsatisfying Sex Scene. Or worse, a Sex Scene That Makes Me Cringe instead of sigh. In the Unsatisfying category: 1) Sex scene was too short/abrupt. 2) There was no foreplay. 3) Man does not seem to know what turns on a woman (or maybe just this woman?) and only goes for his own pleasure. In the Sex Scene That Makes Me Cringe category: 1) Man is hairy. 2) Man says, "spread your legs." 3) Man shapeshifts into a bird. 4) Biting. (Those are all real examples from romances I've read.) Now, there are of course a whole bunch of categories of both romance and erotica out there with huge followings, where things that make me cringe are exactly the things other readers are looking for. Call me old fashioned I guess.
To me, it's the tiniest things that can build massive sexual tension. Here's an example from The Omaja Stone:
“Keep quiet,” he whispered roughly near her ear. “There’s a soldier nearby.”
Jiandra recognized Yajna’s voice and nodded. With a lithe movement, he reached behind her to grab Otto’s reins, then led him along with Jiandra quickly through the trees, around to the rear of the cottage.
In a few moments they came to a creek, and he led Otto to it for a drink. He patted and stroked the horse’s neck as he dipped his tongue into the water. Otto paused in his drinking to nudge him affectionately with his nose.
“He likes you,” Jiandra whispered softly.
“Yes. I used to train horses back home in Nandala. This one is a good boy, and you handle him well.”
She blushed a little. “Oh, I doubt that.”
“It’s true. I don’t give compliments frivolously.”
She pressed her lips together and studied his profile. “Gods, you gave me a fright back there. I am glad you're all right, though.”
He glanced up at her, his expression unreadable. She stared at his angular jaw and chiseled features. His exotic silver eyes were rather striking, and he was flat-out gorgeous, despite his grim demeanor. She cleared her throat. “And the others? Are they all right?”
Now of course I like these types of subtleties (her noticing how her horse responds to him, which gives you a little foreshadowing of how she might respond to him :-)) since I wrote it. But I wrote it that way because the greatest romance novels I've read do that same.
Let me know your thoughts on this topic, if you dare, in the comments below!