The "butter tax," is an England tradition that dates to 1942 or slightly before, wherein it is considered a polite practice or fairly common place to take (without asking) a small knob of butter, when you visit someone else's house in the Cheshire region of the UK. The practice stems from the mid second world war days, when if you visited or met up with a neighbour/friend it would be common practice to steal a personal amount of butter to use for your own means.
P1: "When you visited Elsa in Malpas, did you implement the butter tax?"
P2: " Yeah man, I took a decent 1/8oz of it. She had margarine too, but fuck that."
Also known as the "Big Head Taxed," it is an added percentage tax to all purchased goods in proportion to the buyer's head diameter.
"You're total is $21.73"
"And how much do I owe you for the Butter Tax?"
"$13.40"