I am looking for a verb/idiom/expression to describe a specific mood/action of people. The term in my question is most of the time used for children in which they are not serious at all and just have fun and try to play games usually and ignore what they are obliged to do in their lives.
The only verb that I have seen is: "to act playfully" which means:
— Intending to be fun rather than serious, or showing that you are having fun.
But although it works, it sounds a bit stilted to me when e.g. a mother wants to tell her child:
1) Tomorrow you have an important exam. Don't act playfully this much, sit and study.
2) Tomorrow you have an important exam. Stop playfulness, sit and study.
What would a native mother say in similar situation to both of my cases instead of what I said? I suspect my sentence works naturally.