What does it mean to put yellow cloth under the bed

Geomantic speaking, it is for family harmony and evil spirits. Yellow cloth usually draws spells on it. If it is simply a piece of yellow cloth, the orthodox meaning of Feng Shui can only be that it belongs to gold or earth, depending on how yellow your cloth is, but from a certain angle, you can also see which faction the owner belongs to. Some Feng Shui masters are Taoists or Legalists, and their yellow cloth has been specially decorated to treat evil spirits and so on, so its scope and function are also very wide, whether it is Feng Shui, Taoism or faith.