Alley Oop-

You turn your body up hill off the lip of the pipe, rotating against your momentum.

Alley-Oop Flat Spin 540-

Take off straight out of the pipe. Drop your uphill shoulder down the fall line and rotate horizontally with your hips or back facing the ground. Your tips basically do a loop toward the fall line.

You can land backwards after 360, or keep going with the 540, dropping your tips into the transition.