Why do you want to throw a layer of felt at the bottom when writing brush characters?

In fact, it is to prevent ink from infiltrating into the back of the paper when writing, which in turn pollutes the rice paper and makes the whole calligraphy work end in failure.

The same is true of painting Chinese paintings. I paint Chinese paintings and have this experience. When painting, you must wear a special wool felt (which is available at the calligraphy and painting supplies counter), otherwise the painting will be a complete failure.