少年你脚踏两船不怕船翻吗
[shăo nián nĭ jiăo tà liăng chuán bù pà chuán fān ma]
This phrase literally means 'boy, you are walking on two boats, aren't you afraid they'll capsize?' It metaphorically criticizes infidelity or being romantically involved with multiple partners simultaneously, warning against possible negative consequences.