Kneel down in front of a wall. If this bothers your knees, kneel on a folded blanket or towel. Spread your knees wider than hip distance apart.
Extend your arms overhead and place your forearms on the wall.
Allow gravity to pull your torso toward the floor. It's OK if your head rests on the wall as well. If you're not feeling this in your shoulders and neck, inch your knees farther away from the wall.