relationship turns sour instantly upon any disputes (slang)
Definitions (粵典–words.hk)
語句、俚語
比喻原本親密嘅親友,一反面就顯出醜陋嘅原有個性 to find out a friend's true evil, disloyal nature, to experience how friends turn into enemies after disputes or conflicts of interest.
佢份人出名心胸窄,唔忠誠,隨時反轉豬肚就係屎,你都係小心啲好。
佢份人出名心胸窄,唔忠诚,随时反转猪肚就系屎,你都系小心啲好。
keoi5 fan6 jan4 ceot1 meng2 sam1 hung1 zaak3, m4 zung1 sing4, ceoi4 si4 faan2 zyun3 zyu1 tou5 zau6 hai6 si2, nei5 dou1 hai6 siu2 sam1 di1 hou2. He is well-known to be narrow-minded and disloyal, can turn from friend into enemy any time, you better beware.
Definitions (Wiktionary)
phrase, Cantonese, of a friend
to reveal one's disloyalty without notice