This has, for a long time, been one of my fantasies. I've never spoken with mandy about it, so I'm not entirely sure what kind of reaction I'll get. Plus (I think) we have very sexually-closed-minded friends. I wouldn't want to mention it to them only to get a 'look'.
Like abaya, I worry that I'd get so into it that I'd want to do more than just look at the couples around us. I guess I'd have to be there to find out.
So Redlemon, no ideas unfortunately, but I feel your pain brother.