what does p-shifting mean?

P-shifting is physically shifting- in other words transforming your physical body into a different shape. In this universe, its unfortunately a myth. Occasionally people in the therian/otherkin community come forward and claim to be able to do this, but so far none has provided any kind of proof. Its generally considered a toxic belief and a sign of insincerity, intent to manipulate, or unfortunate active delusion.

(There’s nothing wrong inherently with being a person who experiences delusion, but passing those delusions on to others can be a problem)

Here is a pretty good link to information about actually possible types of shifting: http://therian.wikia.com/wiki/Therianthropic_Shifting_types

My personal belief is that the reason p-shifting is impossible in our universe is that the background mana/magical level is generally too low to allow it.