Happy mother-in-law generally means that in rural areas, some couples get married, and the groom's mother is called mother-in-law. On the wedding day, the groom's parents are called father-in-law and mother-in-law.

If it is at a formal wedding, then Xi's mother-in-law refers to "the person who is blessed". Generally, there are two old people whose spouses are still alive and whose children are "all blessed people". They can serve the couple at the wedding, which means good luck.