Yo Mama and The Titanic

Listen up, buttercup. This joke is saying yo mama so fat, she ain't just big, she's *Titanic*-sinking big. Like, remember that iceberg that took down the ship? Yeah, she's bigger than that! I bet you didn't know that the Titanic was said to be unsinkable, but it definitely sank. That's what happens when you underestimate an iceberg.