靠得住豬乸會上樹 [－－－猪－会－树]

Jyutping kaau3 dak1 zyu6 zyu1 naa2 wui5 wui4 soeng5 syu6
Pinyin kào4de5zhu zhū ná huì shàng shù

Definitions (CC-CANTO)
  1. when pig flys; impossible; a phrase to express disbelief in someone's reliability or trustworthiness [colloquial]