Matsume San,
My GF and I enjoy having another lady join us once in a while but don't like just picking up some bar girl. We've also talked about another boy joining us.
We would really like to have a happy ending massage together during a special night at a Shanghai hotel, with either a M and F massage "therapist" or F F. Any ideas where we can find an out call service who provides these services?

Seamate,
Are you kidding? This city is full of massage places that can give you both a good time. Just make sure you get a private room and your girl asks for a male to give her an oil massage. This seems to be the morris code for "I'm a horny bitch and my sahara needs a little wetting before the camels die". Always works for me, EVERYTIME, and I promise you that this has worked not only in cheap places but also in the high-end 'expat' places. And they don't seem to care if your there or not.
Now the FF maybe a little trickier, never tried to ask for two, especially with a bf around. But i say, fuck it, just ask. It ain't gonna kill ya. Maybe not at dragonfly but I do know of a spa on the second floor of a hotel which I think will provide. It's in the Sh___h__ Hotel behind the Hilton:)
And of course the easiest is craigslist, casual encounters, volunteers only here. Or better yet, under the services section, click on erotic. This is where all the ladies and boys are if your willing to pay a price for what you want.
Give those a try. If none of those work, well, you have my email:)