This is a stretch you can do for your low back before you get out of bed in the morning and before you go to sleep at night.
You'll be lying on your back with your knees bent, your arms out to the side, and you're going to let your knees drop over to the side just as far as it feels comfortable. You should feel a gentle stretch. Stay there for about five seconds and then drop your knees over the other side.
You should feel a stretch across your side in the low back area and maybe across your hip a little bit, and then go over to the other side.
This helps to get everything in your low back loosened up. If your back is feeling really stiff and achy, you can do it in the morning before you get out of bed and at night before you go to sleep.