Translation:The mother says to her son that he is playing with fire.
In Italian if you tell someone he's playing with fire you mean he's doing something dangerous.
Generally annoying people not something directly dangerous for your health. So is also a threat like the mother telling the child that his behaviour will no longer be tollerated.
I think it has the same meaning in English.
Yes you're right. It has probably the same meaning as in Italian. Probably the son is doing something wrong and the mother says "you're playing with fire" but she mean "your are making me angry. Stop it or you'll be scalded"