班主任是容嬷嬷走丢的孩纸
[bān zhŭ rèn shì róng mā mā zŏu diū de hái zhĭ]
A creative and playful statement which means 'The class advisor (often called 班主任 in Chinese school culture) is like Mama Rong (an authoritarian nanny character from a popular drama). A lost child from her, so mischievous'. It is used to humorously describe someone, usually a teacher or mentor, who seems strict or severe but also evokes sympathy. Or someone who acts mischievously or naughtily under such strict figure.