The concept is very simple; one would take an elevated table or box with two sides on it, with the front and back open and exposed. The dog is placed in the box with an over-head beam and a harness that is fastened to the dog, so that it does not slip off. It is important to use a very slippery surface; we use sheet metal. The decoy then approaches the dog from the front end. When done correctly, the dog has no choice but to use only his jaw power to bite. This is only effective if your protection dog has already developed their bite. This is very advanced work and should only be done with experienced trainers.