"A yoga method that can be added to daily oral hygiene.... for removing tartar and its resident bacteria from the tongue. This involves using the edge of a straight piece of metal or plastic to scrape the top of the tongue forward from the area right in front of the taste buds." http://www.aypsite.org/313.html
I had read this, and recalled my father teaching me to brush my tongue, but I'm embarrassed to admit, I never practiced it until recently when my dentist gave me a free tongue scraper. http://en.wikipedia.org/wiki/Tongue_cleaner
It is great having a clean tongue. Feels healthy, and fresh.