For all my grammatically correct friends.

On his 74th birthday, a man got a gift certificate from his wife.

The certificate paid for a visit to a medicine man living on a
nearby reservation who was rumored to have a wonderful cure
for erectile dysfunction.

After being persuaded, he drove to the reservation, handed his ticket
to the medicine man, and wondered what he was in for.

The old man handed a potion to him, and with a grip on his shoulder, 
warned,

'This is a powerful medicine. You take only a teaspoonful, and then say 
'1-2-3.'

When you do, you will become more manly than you have ever been in 
your life, and you can perform as long as you want."

The  man was encouraged.  As he walked away, he turned and asked,

"How do I stop the medicine from working?" 
"Your partner must say '1-2-3-4,'" he responded, 
"but when she does, the medicine will not work again until the next 
full moon."

He was very eager to see if it worked so he went home, showered, shaved,
took a spoonful of the medicine, and then invited his wife to join him 
in the bedroom.

When she came in, he took off his clothes and said, "1-2-3!"  
Immediately, he was the manliest of men.

His wife was excited and began throwing off her clothes,
and then she asked, "What was the 1-2-3 for?"

And  that, boys and girls, is why we should never end
our sentences with a preposition, because we
could end up with a dangling participle.