Yoga is more than just a physical practice that you do on a mat in a class full of students, it's a holistic practice that involves the mind, body and spirit, and involves cleansing practices designed to rid the body of ama (toxins). Tongue scraping, is my favorite cleansing practice, it's been a daily habit since I discovered it and is an amazing way to start the day. On those days when I really don't want to get out of bed I have found that after tongue scraping I feel like my head is clear and I have energy to start the day, and even when I wake up feeling great I notice an extra energy kick after tongue scraping.
Tongue scrapers can be found in health food shops for around $10- $15 or if you are lucky enough to have an Indian grocer nearby like me you can grab one for $2.50. You can also just use a spoon to scrape your tongue but I think a tongue scraper works better.