丩少年别得瑟丩姑娘别淡然
[jiū shăo nián bié dé sè jiū gū niáng bié dàn rán]
'Teenage boy don't show off, teenage girl don't be too cool', suggesting an attitude of advice. It implies some guidance or reminder for teenagers: do not behave excessively or stay overly calm and detached, implying one should act more down-to-earth and genuine.