All grapplers (judo guys, wrestlers, jiu-jitsu folk) use the back bridge - aka neck bridge - as a fundamental exercise. Most put their weight on the top of the head and both feet. The version taught by Matt Furey adds a curve to the upper vertebrae (think Gothic arches) by rolling the weight onto the forehead.
Here I'm demonstrating an advanced form. Note my forehead on the mat, arms on chest (so no assistance from hands), and a three-legged cat's tail in my ear.
This is what happens when you engage the Paddymonster as a coach. I'm pretty sure that Mrragh-agh-agh means One More Rep. Except when it means Feed Me Now.