Do it on your own time.

　　请用自己的时间做这件事。(请在业余时间做这件事。)

　　explain:“your own time”means the time you are not working for somebody else, or the time you are not sharing with other people.

　　场景举例: You are in the office and you are getting paid for working in the office.But you suddenly make a phonecall. You are calling your friends and making doctor's appointments and trying to set up arrangements for the weekend. And this time your boss comes and says to you: "Do it on your own time". Definitely, working time is not your own time for doing personal things.