The Double Ninth Festival is autumn, so it's just the time when chrysanthemums are in full bloom. Therefore, the Double Ninth Festival actually has a nice name, called "Chrysanthemum Festival". Drinking chrysanthemum wine on the Double Ninth Festival is also a popular folk custom in ancient times. Jiujiu is homophonic with "Jiujiu" and also homophonic with "wine", so it is deduced that Jiujiu should drink chrysanthemum wine.