One night as we lay in bed, you tell me that you feel like having sex. I tell you that I don't feel into it tonight, but I would be interested in watching you masturbate while I lay next to you. I've been less sexually active than normal, and when you start talking I'll let you in on why: I have deep, dark desires and fantasies that I'd like to explore with you. As soon as I begin describing them to you, I observe that you become noticeably more aroused, and before you know it, you've agreed to participate!