铁打的青春流水的宴席
[tiĕ dă de qīng chūn liú shuĭ de yàn xí]
A metaphor meaning that youth is enduring but opportunities and moments of celebration are fleeting. 'Youth lasts forever, feasts come and go,' signifying that although one may live for long periods (like strong iron) our precious youthful experiences cannot be held onto and change often.