First off, I think it's VERY important to clarify some physics of disc flight because much of what people have said above is incorrect, misleading, or vague.
Stability is generated by the spin a disc is thrown with, not speed. That is to say, the direction a disc spins is the direction it will naturally fade. This is why RHBH shots fade left and RHFH shots fade right.
The Innova rating system applies a number to a disc's "speed" - that number is *NOT* the maximum speed the disc can fly - it is the speed at which the disc will fly straight. Exceeding that speed will likely cause the disc to "flip" or "turn-over" To help illustrate this, consider throwing your putter as hard as you can - no matter how much spin you put on the disc, it should turn over quickly - that's because it's easy to throw the disc faster than the speed at which it will fly stable.
Additionally, when considering the physics of any disc, one need account for the "high speed turn" and "low speed turn" of a disc. Those two characteristics refer to the performance of the disc against the wind. The shape of the disc - the rim and flight plate - determines how a disc will behave. Negative numbers in either category mean less stable, while positives mean more stable. That is, when throwing a straight or hyzer shot, less spin is needed when throwing an overstable driver and vice-versa with anhyzer or understable drivers.
Okay, now that I've clarified the physics of disc flight I can address the initial question. A hyzer flip any shot that starts on a hyzer line but turns into an anhyzer sometime after it was released from the hand. This shot is very different from a shot that starts off with anhyzer and naturally works it's way back to hyzer relying on the stability of the disc. Such a throw will generate an "S" shape, but the hyzer flip can actually make a double "S" line.
More specifics on the physics of a hyzer flip: The point at which the disc "flips" or "turns over" is when the speed the disc is traveling forward is becomes greater than the speed at which the disc is spinning. Therefore, hyzer flip shots are much easier to throw with understable discs. A disc throw at or slightly above it's maximum stable speed with a tremendous amount of spin will continue to go straight for a long way before flipping. I call that shot a "late-flip" as the disc will not turn over into an anhyzer until it has already traveled 200 or more feet. Such a shot may finish anhyzer or may fade back to hyzer, making a double "S" line as mentioned above. Such shots tend to maximize distance, with only rollers going farther.
Since I'm on the subject, it seems to make sense to talk about anhyzer flip shots as well. Using the same principles outlined above, it is possible to throw a shot that starts off with anhyzer and finishes with even more anhyzer but not falling to the ground or rolling. Depending on the fairway, such a shot usually need anywhere from 30-50' of initial height. If, when the disc reaches the apex of its flight, it's forward speed exceeds the speed of the spin, it will go from a forced flip to a finessed flip and will likely glide out on the anhyzer line.
Finally, RHBH and RHFH players are all different - neither styles have any natural advantage when switching to the opposite style. The ease of switching styles is entirely in the player. That said, a solid understanding of the physics of disc flight will help any player throw in any style. All of the principles I've outline above directly apply to backhand players as well. Choosing which shot to take with which disc is what will make or break a drive. It is not the disc's fault if the drive goes wrong - it's the player that made the mistake of misjudging a disc or misusing form.
