He teaches during the week and then moonlights as a waiter on the weekends.

他在工作日教书，然后在周末兼职当服务员。

You mean like driving a Didi or food delivery? I have a friend who moonlights as a Didi driver.

你是说开滴滴或者送外卖吗？我有个朋友就是兼职做滴滴司机。