Sit on the floor and bend both knees, so your left knee is stacked over your right ankle, and the shins are as parallel as possible. Flex the feet to feel a stretch in your calves.
Press your fingertips into the floor behind your pelvis, or to make this pose more intense, place your hands in front of your shins and walk them out as far as you can, folding your chest over your legs.
Enjoy this stretch for five breaths, then repeat on the other side.