Double vagina is exceptional. I became addicted to it with a couple I was seeing, about every 3 weeks for about 3 years. Takes a lot of leading up until the lady is raring to go, and when she was, no lube was needed- very turned on but not even a squirted. It only worked when I was underneath and her husband came in doggy. Feeling the other cock slide in is amazing. The lady reaction is almost nuclear. Getting a rythym going is incredible- feeling the cock sliding up and down on yours, one in one out. Unfortunately lying underneath you can see nothing, and you have to support the lady who is pretty well out of control. With the other guy shouting, the lady almost yelling, it fast goes out of control then you feel the other guys cock pulsating and coming over yours and it gets fucking messy! Until you get used to it, lining up and successfully staying in can be difficult, but suddenly it becomes so easy. Everyone cums powerfully, the lady multi-orgasms or has one long continuous one (so unfair that!). It's so hot we couldn't make it last long so it makes a wonderful finale! The other guy and I really looked at each other in horror once when cuddling after she moaned "I want more!"
It gave me a taste for frottage which I indulge in occasionally- it makes a pleasant change from my regular female partner who won't play MMF at all. If you get neurotic whether cocks touching means gay, then just don't do it. Cocks touching inside a vagina? Yes please! Goes without saying the MM must be very comfortable with each other's presence and even playing to let her get a rest. It won't work if they shirk at the touch of another cock or jizz. To start with it you have to leave your inhibitions totally behind.
When you look at the thickness of 2 very hard and curved cocks pressed up against each other, it never ceases to amaze me how they can both squeeze into that gorgeous delightful little slit. It was my very best sexual experience. If you fancy it, you must try it, even if it's with an escort couple just to clock up one. Gorgeous!