Little Johnny wanted to know what magic was

So he asked his mother "mommy, what's magic?"
"Dear, I'm far too busy, ask your brother" she replied.

So Johnny went and asked his older brother Dave. "Hey Dave, what's magic?"
"None of your business, ask someone else!" Dave snapped.

So little Johnny was left to ask his odd Uncle Randy. "Uncle Randy, what is magic? Mommy and Dave won't tell me?"
"Oh boy," Uncle Randy started. "Magic is easier shown than explained. Drop your pants and undies and turn around."

Trusting Uncle Randy, little Johnny dropped his trousers and underpants and spun around. Uncle Randy walked up behind Johnny and asked "Well, little Johnny, do you feel my thumb in your butt?"

"Yes..." Johnny whimpered quietly.

Uncle Randy waves his thumbs in Johnny's face and goes "Iiiiit's maaaaaaagic!"