I'm writing my first YA sex scene. Yikes! I think there's a fine line between describing too much and not enough. Kids know what's going on. In middle school I was reading Judith McNaught novels. I knew what was going on, and that was before the widespread use of the Internet.
But as I was writing it, I found myself taming it down, and losing something.
My day job is a creative position as well, involving product and packaging design. When I first started working here, I was designing a box and trying to be conscious of the color usage because more colors means higher cost. The marketing manager at the time said to me, "Don't worry about that. Let the printer worry about it how to make it work. That's their job. Your job is to design."
She was right and that stuck with me. My job is to design. So I do, using as many colors as I want, and after it's done we work with the printer to see what we have to change to get the cost down, and sometimes we don't change anything because the box is that good.
It's true with writing too. My job is to write, and in a first round, I should include as many details as I feel necessary to describe the scene. Later I can edit it down, or I can decide to keep it as is, and let my crit partners or agent tell me to cut it. If I limit myself in the beginning, I'll never know what the scene could have been, what it would look like with six colors instead of two, which might be worth the extra cost.