The dress is fluttering, which means that the skirt sleeves are flying with the wind and the fairy dust is fluttering. The article refers to the way girls' skirts fly with the wind, which describes women's youth and liveliness, so it is used to describe girls.
Dress fluttering, a word originated from ancient poetry and novels, describes the scene of women's gorgeous clothes fluttering in the wind, which generally refers to fairies or goddesses in ancient Chinese.