Devouring Everything, Starting from Eating Grass

I have a big stomach bag, where I can eat the sun, moon and stars from above, and birds, fish and insects from below. Stomach fire burns the sky and can melt all things. Everything in the world is instantly refined as soon as it enters the stomach. Certainly! That's later. Now there is a difficult question before Wang Li. What should he do if there is not enough grass to eat?