What's a flip? It's not popular, that's the first thing. But re my last post, maybe it's sometimes necessary.
The "flip" maneuver is when you use the same arm to indicate a change of direction, instead of a change of arms. Sometimes there just isn't time to change arms. You're running too fast, or there's not enough room/time to maneuver, whatever.
To train the flip, I guess you'd do some flatwork (without obstacles). If you put D in heel position right, and want D to make a right U-turn away from you, hold a treat in your right hand, by D's nose and have D follow the treat as you draw an upside down U, away from you. You would not actually turn your own body around (because if you could do this, you wouldn't need the flip). Treat immediately when D's U-turn is completed. Repeat both sides. Use up a lot of treats.
This is different from RC training where H also makes a U-turn in the same direction while remaining on the nearest side of D, and H delivers the treat from the opposite hand, which gets D used to H crossing behind him.
It's hard to talk about this on paper. Sometimes a thought experiment and diagram just won't work. You have to get out there and experience it for yourself. All I know is, I have experienced many moments when a flip seems to be the only solution and if it's easy to teach it to my dogs, why not teach it?