double Fly
Sorry, it has been a looooong time not getting on this forum.
For my exprience with double fly is that don't ignore girl, usually during the DF, you may find one that you like fuck her more, may be her breast, her BJ, her moaning, her juicy cunt whatever, you probably spend more effort to screw that one. that is the big mistake I made for the first times. In order to maximize the interaction between the girls, you encourage them to touch each other. finger them the same time, lick the boobs alternatively, don't concentrate one only, once they feel you are attractive to them both, they usually becomes more cooperative , opens up and more interaction between them. Trust me once you arrive that stage, it is time to sit back and enjoy the fruit of your hard work. keep them busy, one on top of you and other will deep french kising with you or ask her lick your nipples while fingering her. Be brave at the end, the best finishing is to have them in doggie style and finish it in one while finering other to finish her the same time. sometime stick your finger into her ass at the end.
I don't do DF all the time but only when I feel both girls will cooperate with each other or you know one of them will lead the role. You need to find the right comination with right chemistry ebfore you commit the DF, otherwise you will simply wasting your money and time.
OO