Setup and Key Actions
Begin in a high kneeling position. Separate your feet a little wider than your hips (just wide enough so that you can sit back between them). Use your thumbs to massage down your calves, helping them to relax as you sit back, but avoid rolling your calves outward. While rolling the calves outward may initially make it easier to sit between your feet, it also puts your knees at risk.
If your seat is far from the floor and/or virasana without support bothers your knees, place a block or folded blanket between your feet and ankles. Your feet should be just outside your hips, the tops of your feet pressing into the floor, and your toes pointing straight back. Your knees don’t have to be together (in fact, for many practitioners knees together isn’t optimal in virasana), but make sure that they don’t splay out wider than your hips.
Then begin to recline back, first walking back onto your hands, then maybe your elbows, and then if it feels comfortable, onto your back (if there’s a block under your seat, you won’t be able to go all the way onto your back unless you also have a bolster or stack of blankets behind you to support your middle and upper back, neck, and head). If you feel discomfort in your knees or lower back, or if your knees lift significantly off of the floor, back out of the pose and come more upright.
For a more supported variation, sit on a block or a blanket folded to about the size of a block and support your middle and upper back, neck, and head with a bolster or stack of blankets behind you.