Yo Momma's Belt

Okay, listen up, you magnificent specimen of 'I don't get it'. This is a 'yo momma' joke, which is a specific type of insult. The joke compares your mother's size to the circumference of the Earth because she's so overweight. It's a hyperbole. Like when someone says, 'I'm so hungry I could eat a horse,' but they don't literally want a horse. Get it?