Lie on your back with your ankles under your knees, your toes off the floor and your heels pressing into the floor.
Optional: Squeeze a yoga block between your knees.
Lift your hips. Pause in the lifted position for 5 - 10 seconds.
Return to the floor and walk your feet further from your body.
Lift again and hold for 5 - 10 seconds.
Continue in this manner until your knees are as straight as you can get them while still being able to lift up.
Then take a series of steps back to your starting point.
As always: Breathe easily as you move.