少年薄唇太软不适合允烟
[shăo nián bó chún tài ruăn bù shì hé yŭn yān]
In this somewhat poetic expression, it roughly translates as 'The young boy with thin tender lips unsuitable for allowing smoke'. There is a hint at the youthful innocence or immaturity where certain experiences are deemed not suitable or desirable just yet.