How is an orthodontic night guard fitted?

Coincidentally I just had this done last week. I need one because I tend to grind my teeth when I sleep. It is not fun getting fitted for a guard. They put a guard with a bunch of what looks like wet clay into a large guard and your teeth get pushed into this stuff and basically molds around your teeth. The toughest part is you have to have this stuff in your mouth for 4 minutes. If you are a gagger like me you will have to ask for some sort of numbing thing to put in the back of your throat. It really helps.

To be fitted for an orthodontic night guard the orthodontist must take impressions of the teeth. In addition, a bite registration must be taken to replicate the patient's bite in the laboratory during the fabrication of the night guard. On delivery of the night guard, the orthodontist must adjust the night guard to the patients bite and functional excursions (jaw movements from side to side and forward).