The origin of this word may be related to traditional wedding customs. In some places in Guangdong, when a man and a woman get married, the man will use a float to pick up the bride at the woman's house, and at the same time, he will prepare some gifts such as candy and wine to express his respect and love for the bride. This custom is called "float to greet the bride", and "happy event in flower field" can be understood as a happy event that happened in this process.
Generally speaking, "a happy event in a flower field" is an auspicious language in Cantonese, which can be used to describe a person's good luck and happiness.