HOW: In a seated position, place your feet on the ground under your knees with your toes facing forward. On the side you're performing the stretch, move your foot back and while keeping your toe on the ground, lift your heel up to move your big toe into extension. Hold for a moment, then lower your heel down and repeat. This stretch may not be comfortable. It is up to you to determine how much weight to put on your back foot – only put as much as you can handle. Go gentle!
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!