Just to add my two cents I think it may be the case that Wudang may have confused anti-matter and something along the lines of dark matter, I may be wrong but that may help clarify the confusion in that part of this at least.
the existince of dark matter is only theoretical and is only proven by the fact that it gives off a slight gravitational pull much like a gyrokinesis vortex...
well its the same as gravity we can measure it but we dont know what creates it. there are many theories put aside for dark matter and gravity but yes we can measure quantities of dark matter but we dont know where it comes from nor how to make it correctly.
As humans we cannot create dark matter nor will we ever understand how it is formed. We're not meant to know everything or anywhere close to everything.
when a person creates a psiball, its natural for the ball to increase in mass as it absorbs energy. Thats one of the basic ways you "manipulate" the energy of the construct.
As for a pulling sensation from the edge to your hands, that is a Normal sensation from creating a psiball. If you happen to think of making it smaller, or condensing it to a more solid mass, the thought causes the ball to harden and shrink in on itself. This effect causes your hands to "want" to move inwards, as you recognise the energy sphere you're holding is shrinking.
Its also normal for your hands to spread as you increase the energy ammount in the ball, and increase its size. Or even to "pulse", the psi tends to give off a sort of in/out pulsing sensation when enough of it is on one place. I couldn't say Specificly why this is, it could be simply because subconciously we believe it to be so. Psi is, as of yet, highly undetermined in nature. At least in the manner of exacts of interaction with the world, whys and hows ect.