姐妹男友不许碰兄弟女友不许泡
[jiĕ mèi nán yŏu bù xŭ pèng xiōng dì nǚ yŏu bù xŭ pào]
This means 'Hands off my sister's boyfriend; no flirting with my brother’s girlfriend'. It represents protective feelings towards family members, particularly in romantic matters involving siblings and their significant others.