If you've been writing erotica for awhile, you might have reached a point where the sex scenes start to feel repetitive, and frankly a little stale. In my own work, I tend to focus much more on characters, relationships, circumstances (i.e. plot), and setting the scene, building up the tension that makes sex inevitable. To me, that's more erotic than the depictions of sex itself. Nevertheless, if it's an erotic story, sooner or later readers are going to expect a fairly vivid sex scene. The genre pretty much requires it. What do you do to keep the sex you're writing about interesting to read without falling back on tired (and often unrealistic) tropes and 'dirty talk' cliches?