Try and Stop Me
There's a lot to be said for research and practice. Case in point: I give a good friend of mine the gift of fan fiction for birthdays and Christmas, starring her and her celebrity crush. A while back, she requested that these stories include *spicy* scenes. As a girl who's never been in a physical relationship of any kind I didn't have any real world experiences to draw on, and I'm not the biggest fan of the romance genre in general. So what's a gal to do with no knowledge base? Make one. Short of throwing myself at random men on the street of course. I watched sex scenes from movies. I called to memory the books with red covers my mom said were for grown-ups ONLY (so of course I had secretly and confusedly read one). Lastly, I looked up a specialized vocabulary list for *spicy* scenes, so I wouldn't sound like the complete idiot I was, and I wrote the spicy scene.
Good friend liked the spicy scene. The con was successful.
Moral of the story: You can write what you don't know if you're willing to learn.