He has hit the udder between the horns.
More Hungarian Proverbs:
The purpose consecrates the means.Hungarian
Nail by, with nail.
Hungarian
He got out of the bucket and got into the pail.
Hungarian
I can chew for you, my child, but you must swallow by yourself.
Hungarian
He has already one foot in the grave.
Hungarian
They match as a stick in a quiver.
Hungarian