This is a very popular stretch that is very refreshing for anyone.  You may know it by a different name, though the phrase “seal stretch” is quite descriptive.

Lay flat on your belly with your hands at your sides and your palms on the ground.  Push up and lift only your upper body as far as your body allows.  You do not want to inflict pain on yourself with this stretch (or any sciatica stretch.)  Lift yourself slowly to avoid straining the muscles or spine, and do not arch your back too much to avoid hurting yourself.