"Knocking on the door" refers to the wine served with a spoon when welcoming guests in a closed room in China. This way of drinking is quite common in Fujian, Guangdong, Guangxi, Yunnan and other places. In these places, when guests arrive at the bride's house during the wedding, relatives and friends of the bride's house will open the guest's door with bamboo hooks, and then pour wine into the room from the crack of the door for the guests to drink. This is the so-called "knocking on wine".

The origin of this way is said to have originated from the traditional customs in ancient China. As early as ancient times, people often used some cloth belts to turn around at the crack of the door to welcome guests. Under normal circumstances, doors are opened by people who welcome guests, but in modern times, doors have been sealed. Because knocking at the door is regarded as offending guests and attracting some evil spirits, the special wine for knocking at the door is for guests to drink. After the guests had finished drinking, the door panels that hit the door and the red strips on the door panels were removed, and the bad luck was released and vanished. At the same time, it also indicates that the bride's family and wedding banquet may have a happy and beautiful future.