Kundalini Yoga practice includes tongue scraping. I have been doing this everyday for 20+ years. Typically done right when you wake up and before you drink water in the morning. I use a copper scraper which adds copper to our already depleted copper levels in our bodies. My favorite one is from Primal Life:
Here's a link for further reading.
If you have any more questions, please feel free to ask!!!
Location:
1270 Rabbit Hollow Road
Northfield, VT 05663