Diana Gabaldon's sex scenes in her "Outlander" series are strong and effective and hot. Her "I Give You My Body" essay is excellent. She has excerpts on her web site.
This passage caught my eye:
"Everything in fiction writing comes down to character, and sex scenes are no exception. If you can replace your characters’ names with Dick and Jane (or Harry Reid and Nancy Pelosi, say*) without substantially altering your scene—you need to think again. In good sex-scene writing, this particular scene could only have happened to these two people."
*Ed. note: Just to make this balanced you may substitute "Donald Trump and [whoever]"
~ JBB
Gabaldon, Diana. "I Give You My Body...": How I Write Sex Scenes (Kindle Single) (p. 8). Random House Publishing Group. Kindle Edition.