Criteria = Take It!
As mentioned before, the criteria you want to mark for the bite is the moment the dog removes the toy from your hand. So when he actually takes it (or you let go), that’s when you mark.
This criteria is extremely important because it allows the handler to easily scale up the intensity from “touch it with your teeth” to “tear it from my hand”. This allows a feeble, apprehensive bite to be shaped into a beastly, aggressive, crack!
Using the removal from the hand as criteria for the bite creates a black and white criteria for the dog. Once he knows exactly what works, he is much more likely to do it.
Most people are focused on the “bite it hard” criteria when it comes to bitework. But what is that? What is hard? What is not hard? Was that one a hard bite?
The removal from the hand is a concrete, black and white criteria. “You either remove it from my hand or you don’t.”
Between the concrete criteria and the sliding scale of resistance that the removal from the hand affords, you and your dog will be putting a good solid chomp on the disc in no time.