This movement is used to gain escaping movement rather than an escape itself.
While on you back get your heels as close to your butt as you can. Tuck your elbows next to your sides and bridge onto your upper shoulders. Using the rolling shoulder motion, walk yourself backward on your shoulders and feet.
This movement is upsetting to a mounted opponent’s base and also buys you room to get your hands into his hips for escaping techniques.

To do the reverse shoulder sprint, do the same in opposite direction: bring your heels to your butt and arch onto your upper shoulders. Now extend your arms flat onto the mat above your head. Then shoulder walk and drag yourself with your feet toward your hips. This movement is a bit difficult. It helps you escape being pinned headfirst against the cage.