Well Personally i think Psi Balls Have To do A LOT with TK i mean TK is a form of Psi so anyway here is how to make one if you don't know how. :)
You Cup your hands together and shut your eyes
Then You flex your arm muscle (keep eyes shut)
Let the energy flow in your hands because that's all psi balls are are balls of energy
Don't worry if you can't see it the 1st time you just need to put more energy in
if you don't believe in this WHY ARE YOU HERE?
just getting your attention ok now back to it
Just keep trying i still haven't seen mine yet but i can feel the energy
if your hand twitches that's ok that lets you know that you might be able to see it
throw it at something and see what it does!