The best I've done is to conjure up a perfect sex partner. (I've only had a couple of recent lucid experiences that I can recall, so I don't have much experience to share other than that.) I didn't know in advance what he was going to look like, but I knew that I'd walk around the corner and find the most perfect man I'd ever seen. Sure enough, there he was, a waiter who had just taken out some trash behind a restaurant and was about to go back inside. When he initially resisted my advance in the back alley we were in, I said, "Shut up. I created you, you're mine, and you're going to enjoy this." And then he did because I wanted him to.