There's a school of thought that (paraphrased) reminds writers to be honest.
In sex scenes, the very first question is: Is it honest? (read as: does it make sense?)
How many times have you felt like throwing a book across the room because you're going WTF!?!? They're running from a homicidal (fill in the blank by genre) and they're doing it?
Then again, I've been re-reading Tara Janzen's "Crazy" series, and while there certainly are a couple of WTF (ahem Red Dog and Travis's first encounter) the lead in sells it.
So, I would promote that the lead in should sell the scene. If your scene is feeling awkward, have you led up to it well enough? Build the tension between the protagonists to the point where it is just inevitable they touch... kiss... whatever.
My first few tries at this were epic fails. Mostly because I didn't take my own advice above.
If you are they type of writer that would rather imply the deed than the actual slot A + tab B or whatever approach, then do like they did in old movies, fade to black. Build the kiss, show the emotion, sell the need. Then close the curtains on the happy participants and move to the next scene.
Imagination is an amazing thing. Some of my favorite "sex" scenes had me re-reading to see why I liked it so much and it wasn't any mechanics that sold the scene (exception: Stroke of Midnight - but maybe it was the growl that sold it...) So choreographing a scene (YES should happen) but can be cleaned up in post too.
Which brings up another pet peeve, "Where'd that hand come from?" Or worse, "Where is he again?"
I read a novel (I read about 200+ a year so...) two weeks ago that had me saying the second question. The set up seemed that he was kissing from the front, but well, unless this woman was very flexible, I'd guarantee she'd have a sore neck from cricking it backwards for so long... Nuff said on choreography.
Good luck, read the posts in the link below, Stacia Kane writes amazing books!