姐胸平照样有霸气
[jiĕ xiōng píng zhào yàng yŏu bà qì]
This nickname translates directly as 'Even though sister's chest is flat, she still has a strong presence/has power.' It can convey that despite lacking physical attributes traditionally associated with femininity or desirability (such as ample breasts), the woman still holds self-confidence and authority.