While scientists agree that bacterial load is reduced by tongue scraping, the consensus is that this practice has to be done regularly in order to reap the benefits. In a 2008 study, the amount of tongue crud (admittedly, not the term used in the scientific abstract, but you get what we’re talking about here) was significantly reduced in subjects who scraped their tongues and brushed their teeth every night, as opposed to those who just brushed their teeth. And while there’s no conclusive hard data on exactly how often you should be scraping, once daily is a reasonable place to begin.
As for how you do it, it’s the simple act of sticking out your tongue—ideally in front of a mirror—and placing one of the flat edges of the device down, then pulling forward. A half-dozen swipes forward, wiping your scraper clean on a tissue each time, and you’re done. Next, brush, floss and rinse with mouthwash.