This is an annual 8.3% tax deducted from everyone's lifetime and given to Mariah Carey.
Every December (1/12th of the year), Mariah Carey's Christmas career, especially her single "All I Want for Christmas Is You", dominates the media and becomes inescapable. Her Christmas media permeates all corners of society and becomes impossible for people to avoid.
Emily: "Wanna go to Florida next week?"
Joseph: "Let me check to see if I have any leftover time after this year's Mariah Tax."