HOW: Get set up at the top of a down dog position with your heels lifted and your weight supported through your toes with your big toe facing straight forward. Perform the stretch by lowering your body down and letting your knees bend while simultaneously letting your heels rise more and your big toes move into extension. Hold for a moment, then return to starting position and repeat.
FEEL: You should feel a deep stretch in your big toe itself, and potentially under the big toe/arch as well.
COMPENSATION: Avoid rolling your foot/ankle out or in excessively as that will create a twisting motion at your big toe joint. Focus on pure linear motion. Only put as much weight as you can handle, this joint is a sensitive one, go slow!