Why is Bing called Sister Mao?

The reason why Bing is called Sister Mao is that in a live broadcast, Rui has a brother who is a fan. His screen name has an uncommon word "Mao" and many gifts are brushed, but neither Rui nor the fans know what this word is reading. Later, everyone knew that the word pronounced Mao, four tones, and from then on there was the saying that Rui called Mao Jie.