The name says it all. You spin on your ass.
This is kinda like a backspin but you never roll down on your back.
1) Sit on you ass with your legs in a 90 degrees angel. Like a backspin.
2) Now kick your right leg over the left leg in a circular motion. Then you should start spin.
3) You will not spin for a very long time. Lean your back backwards. Not to much an spread you legs up. So your upper body and your legs are in a 90 degrees angle.
4) Keep on spinning as long as you want.
That´s it ya´ll!!!