As a mere mortal, I can perform a 360 dunk only if I jump off a trampoline. Make that a bouncy trampoline. A really bouncy trampoline. To get high enough to spin before you dunk it, an unathletic shrimp like myself needs an extra boost.
But even on a really, really bouncy trampoline, I couldn’t do what Deron Washington does in this highlight. Not only does he do a 360, but he does it the wrong way, and while putting the ball between his legs. What’s the wrong way? Try doing a 360 on a 6-foot rim. You’ll intuitively spin one way. He goes the other.