Below are a couple links to questions asked about patients with a gag reflex. They are more geared to gaggers and X-rays, but the same techniques can be applied:
https://www.dentalhygieneanswers.com/severe-gagger-with-x-rays/
https://www.dentalhygieneanswers.com/gag-reflex/
Thanks Kara!
DH95
You are most welcome!
Kara RDH