I've only had two sexually explicit dreams in my whole life. One really didn't make much sense though. In this dream I was a chick, and to speak in technical terms, i was really getting nailed by a some guy. I could go on with deets, but I'm not sure what's appropriate. In the dream it felt awesome, real "tickly" I guess. It just seemed like an everyday thing at the time. I've never dreamt of being the opposite sex before, especially in that situation, so I'm stumped on this.
It could be curiosity. It could have to do with thoughts about the role you play in life as a guy. It could have been you getting in touch with your feminine side - meaning your creative, intuitive, sensitive side.