Joe
I have never practiced it and someone please correct me if I am wrong.... But I believe it is the Hood training method where you Tid bit the Bird up high at head level while hood training.

I believe this is done by putting the tid bit -in the hood- and letting the hawk take it thus conditioning the bird to associate it's beak in the hood as a good thing. The intent is to allow the hood to be placed on the bird later as a natural next step without creating a negative association.

I have only seen this done and assume this is what your referencing. High level tid biting can be done under other circumstances as well. But it is specifically offering a tid bit at head or above head level to the hawk. The idea is to take the feet and eating at the feet out of the equation.

There are two problems with these methods that should be considered. Some Falconers reason that food shouldn't be involved in Hood training because it teach's the bird to expect food while or when hooded. Behavior such as biting while hooded or tearing at the hood itself is a risk.

the other problem is that when high level tid bitting is done it often includes your hand. The hawks impulse is to grab you with it's feet or bite. Plus the tid bit isn't visible to the bird until it's offered so the hawk is constantly looking at your hand for food. Some speculate it encourage's the hawk to grab you.

I am sure someone else could elaborate better. But that's how I understand it.