This exercise brings energy to your immune system to fight infection. It is a very healing exercise. When you feel a tingling in your toes, thighs, and lower back it is an indication that you are doing this exercise correctly.
The Practice
Posture: Sit in Easy Pose with your chin in and your chest out.
Breath: Stick your tongue all the way out and keep it out as you rapidly breathe in and out through your mouth. This is called Dog Breath.
Continue this panting diaphragmatic breath for 3-5 minutes, then inhale, and hold your breath for 15 seconds and press the tongue against the upper palate. Exhale. Repeat this sequence two more times.
This kriya can be found in Praana Praanee Praanayam.