There are several ways to coat bamboo with pulp:

1. Hand-to-hand play: Keep wiping and touching the surface of the bamboo with your hands, and slowly remove the sweat and grease carried by your hands. It penetrates into the interior and oxidizes and hardens when exposed to air to form a patina. As the playing time continues to increase, the sweat components, sebum components and oxidation will cause the bamboo to slowly turn red.

2. Lighting conditions: Place it directly in the sun to receive exposure. Through constant light and oxidation conditions, its color will fade and slowly turn red. However, it is recommended to soak the bamboo in salt water for a period of time before exposing it to the sun to prevent it from being unable to withstand the sun and causing cracks.

3. Oil replenishment: Bamboo likes sweat and oil. You can add some olive oil, walnut oil, etc. These oils will form a protective film when exposed to natural oxidation in the air. After a period of time, the outside of the bamboo will harden. The color of the bamboo will change if you play with it for a long time.

In short, no matter which method is used, patience and careful care are required to get the bamboo to be coated with pulp.