A man walks into a Doctors office and puts a note on the table in front of the Doctor.

The note says: "I can't talk, help me!"

The Doctor thinks for a while and says to the man, "Put your penis on the table here."

The man thinks this is a bit weird but does as he says.

The Doctor takes a rubber mallet and hits his penis with it as hard as he can.

The man cries in great agony: 'AAAAAAAAAAAAAAAAAAAAA.....' 

and the Doctor says, "Good, come again tomorrow and we'll learn B