What does Anvil Day mean?

Anvil Day meaning in Urban Dictionary

A holiday celebrated on December 23. I started in 1264. It started when the neighbor kids had been running around the Blacksmith at the office. Then he dropped his anvil to them since they disracted him. He lied and stated which they had been "screwin' around too much" Ever since then, He dropped anvils regarding young ones that "screw around way too much" heads as a warning that they should get coal for X-mas.