Yes, I am serious (as serious as I can be, anyway!). It was a question from a friend that has intrigued me, especially since I (we) can't seem to find any specific answer(s).
"prick' is probably translitterated into 'perk' but it is still what I consider to be a colloquial(?) remark, not a defined term. It seems to refer mainly to the erection of the ears, not the other movements (individually or in tandem) I'm talking about.
'focusing' may be the closest we get! It is certainly indicative of what is happening.
I also like "EARly warning system!"
I can 'wiggle/move' both my ears at once, and you can too. Just shake your head back and forth! It's a little harder (and possibly dangerous! ) to move them individually!
Jim C.