After a few years of married life, this guy finds that he is unable to perform anymore. He goes to his doctor, and his doctor tries a few things, but nothing works. Finally the doctor says to him, "This is all in your mind," and refers him to a psychiatrist.
After a few visits to the shrink, the shrink confesses, "I am at a loss as to how you could possible be cured." Finally, the psychiatrist refers him to a witch doctor.
The witch doctor tells him, "I can cure this," and throws some powder on a flame. There is a flash with billowing blue smoke. The witch doctor says "This is powerful healing but you can only use it once a year! All you have to do is say '123' and it shall rise for as long as you wish!"
The guy then asks the witch doctor, "What happens when it's over?" The witch doctor says, "All you have to do is say '1234' and it will go down. But be warned, it will not work again for another year!"
The guy goes home, and that night he is ready to surprise his wife with the good news. So, he is lying in bed with her and says, "123" and suddenly he gets an erection.
His wife turns over and says, "What did you say '123' for?"