This kind of behavior is called knot hair, which is the custom of traditional marriage. A ceremony symbolizing the union of husband and wife. When a husband and wife get married, they each take a hair from their heads, tie it together and tie a knot, and both men and women become husband and wife.
Extended data:
Ancient wedding
Book of Rites Quli Shang: "If a woman promises to marry, she must marry." Fringe is a colorful silk rope, which is used to tie women's hair after marriage. Zheng Xuan's note: "Dai Ying, knowing the relationship." In other words, the tassel is a sign of engagement, indicating that this woman has met someone. The bridegroom didn't untie this hair rope until the wedding night. This is what is said in "In the Soul of Li Yi's Poems": "The master (husband) enters the house and takes off his wife's tassel."
Therefore, English is always the token of husband-wife relationship. At first, tying one's hair refers to tying a tassel when a woman promises to get married, and later refers to tying a tassel when her husband gets married. This is what the ancient poems say: "When you are married, there is no doubt about your love" (Su Wushi's poem) and "When you are married, the banquet will not warm the king's bed" (Du Fu's "Newly Married").
There is another explanation, that is, the traditional explanation, that is, when a man holds a coronation ceremony and presents on the fifteenth day of the year, his hair should be tied in a bun, which is different from his childhood hairstyle, indicating that he is an adult and can get married. In Selected Works, Su Wushi notes: "When you get married, you become an adult, which means that when a man is 20 years old and a woman is 15 years old, the crown is the righteousness."
In ancient China, people got married when they were young, which was called knot hair. Later, because the "knot" used for marriage refers to the original husband and wife.
Sometimes it also refers to when you were young, such as "Biography of General Li", "Fighting against Xiongnu with the ministers".
Knots also mean that newlyweds must cut off a lock of hair before drinking a toast, and they will be together to show their concentricity. Su Wu has a poem, "Get married, love each other without doubt".
Reference source: Baidu Encyclopedia-Jiefa