Definition
An expression used to tell someone to start being helpful.
别闲着，帮忙去
Since you're here, you might as well make yourself useful and help out instead of just standing around.
既然你在这里，不如做点有用的事帮忙，不要只是站着。
If you want to stay here, you should at least make yourself useful and not just sit around.
如果你想留在这里，至少应该做点有用的事，不要只是坐着。
Stop complaining and do something to make yourself useful.
别抱怨了，做点有用的事吧。