Take the case of a male point of view. I like penises. I’ve played with my fair share. And I’m a human who doesn’t believe that men are from Mars and women are from Venus — we’re both from Earth, and we have a lot in common. I probably wouldn’t hesitate to write a non-erotic story from a man’s point of view. Erotica, on the other hand, intimidated me, since such an undertaking would necessitate describing how it feels to have a cock.
This came up a lot when I was working on my e-book The Six Swans, which was entirely from a male point of view. But since I conquered the fear with that piece, I've found myself writing from the "other side" more frequently. Less Than a Day, for example, came very naturally that way. And I recently contracted for my first m/m story.
If you'd like to see my mini writing lab on how I leveraged my own sexual experience to pry my way into the head of the opposite gender, you can read the full post at Erotica For All.