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."