He plays with somebody as a cat plays with a mouse.
More Hungarian Proverbs:
If the cat's away, the mice will dance.Hungarian
Come a little closer when your sword is too short.
Hungarian
A prudent man does not make the goat his gardener.
Hungarian
Truth may be told in a joke too.
Hungarian
A shy beggar has an empty scrip.
Hungarian
Nail by, with nail.
Hungarian