少年嘴唇多软不适合吮烟少女心多脆弱不适合受挫
[shăo nián zuĭ chún duō ruăn bù shì hé shŭn yān shăo nǚ xīn duō cuì ruò bù shì hé shòu cuò]
It contrasts the innocence and fragility of youth, suggesting that young lips are too soft for smoking and young hearts too fragile for setbacks. It expresses the purity and vulnerability of youthful feelings.