What is the pudding rule in sushi go?

Excuse me, but I'm curious about a term I've heard in the world of sushi-making: the pudding rule. Could you please explain what exactly the pudding rule entails in the context of sushi preparation and presentation? Is it a guideline related to the texture, portioning, or perhaps the order in which sushi ingredients are layered? I'm eager to learn more about this intriguing aspect of sushi go!