Stepping on the gourd cover is stepping on the manhole cover. China has a history of 5000 years, and many customs have been handed down from ancient times to the present, which we call traditions or customs. For example, we will eat zongzi on Dragon Boat Festival, and Tomb-Sweeping Day will go hiking to worship his ancestors. Many customs handed down have feng shui taboos, and stepping on the manhole cover will be hit three times. This custom is more common in the north. Northerners think that there are a lot of sewage and sundries under the manhole cover, which will cause Yin Qi to rush up and the air is dirty. Therefore, people who step on the manhole cover will be unlucky again and again because of Yin Qi, and their health will be damaged. The way to break bad luck is to leave the manhole cover quickly and hit your head three times in a row. I guess many people have been beaten by friends from the north who traveled together.