One of the ways we trained Sempi to say "Please" and "Thank you" is by asking him "What do you say?" after he receives a favor from someone. With that context in mind, this conversation happened in the car.
Vian: Can I have that monster truck, Sempi?
Sempi: Here you go.
Vian takes the truck. Sempi being the responsible older brother wants to teach Vian good manners.
Sempi: What do you say, Vian?
Vian: Vrooom, Vrooom.
Sempi just shakes his head and mumbles something that vaguely sounds like "Kids these days".