A man went to the doctor's office to get a double dose of Viagra.
The doctor told him that he couldn't allow him a double dose.
"Why not?" asked the man. "Because it's not safe" replied the doctor.
"But I need it really bad" said the man. "Well, why do you need it so badly?" asked the doctor.
The man said "My girlfriend is coming into town on Friday; my ex-wife will be here on Saturday; and my wife is coming home on Sunday. Can't you see? I must have a double dose".
The doctor finally relented saying "Okay, I'll give it to you, but you have to come in on Monday morning so that I can check you to see if there are any side effects".
On Monday, the man dragged himself in; his arm in a sling. The doctor asked "What happened to you?" The man said "No one showed up".