Happy One is right. What are you looking for in a two girl meet ?
I've tried it a couple of times but the reality never lived up to the fantasy
Think of it this way. You've got one dick and they have 6 orifices (between them). Where do you start ?
Maybe you want to watch some girl on girl action but, unless they really are into each other, it generally comes across for what it is - acting.
For me, MMF is far more of a turn on