Analysis of information sources in references of the Wikipedia article "伴娘" in Chinese language version.
[I]n polite society...the bridesmaids' only duties are to make a special fuss over the bride by gathering around her at the wedding and, in the weeks before, by pretending to be interested in all the wedding details. It is also nice, but not obligatory, for them to plan a girlishly informal gathering—a luncheon or shower—for her beforehand.