I've thought about that as well, but for me seeing another guy takes the fantasy away that it is me involved. I have wondered if, instead of showing the guy, when the [gorgeous] gal is down on her knees in front of the imaginary guy, you couldn't just show the cock itself with her stroking it. That way I could still play the role of the brother, roommate, son's mate, whatever. By doing what you are suggesting, I become a spectator rather than a participant.