|1.||Quack Quack Seatback|
Similar to "Fives" or calling "shotgun", "Quack Quack Seatback" is a common way to lay short-term claim to a seat you're about to vacate when with a larger group. Sometimes shortened to "Quacks."
Person A: "Hey, you stole my seat."
Person B: "It's my seat now."
Person C: "No, he called Quack Quack Seatback. Move it."