Warning: This exercise is not for the faint of heart. Or lungs. You have been warned.
Step 1: Find a comfortable position, preferably not on the floor.
Step 2: Inhale for 30 seconds, or until you feel lightheaded.
Step 3: Hold your breath, and pretend you're a statue.
Step 4: Exhale, and repeat until you're not sure what's happening anymore.