Siren, I understand having the fantasy of doing this and with my first wife, we would work through the scenario to bring her to climax; usually involving one of her close friends. We had discussed it and I personally said if we did I only wanted to be "in her" and not the other woman. Also there can be no jealousy involved but at the last minute you might realize oh I am sharing my partner and I don't like that. I would say don't try it, but if you do be safe. Also think of other ways to rev your engine and get wet, maybe try taking it slow and easy too. Well okay then enjoy.