On my 60th birthday, I got a gift certificate from my wife. The
certificate paid for a visit to a shaman living on a nearby reservation
who was rumored to have a wonderful cure for erectile dysfunction.

I drove to the reservation, handed my certificate to the shaman, and
wondered what I was in for. The old man slowly and methodically produced a
potion, handed it to me, and with a grip on my shoulder, warned, 'This is
powerful medicine and it must be respected. You take only a teaspoonful
and then say '1-2-3.'

When you do that, you will be more manly than you have ever been in your
life, and you will be able to perform as long as you want.'

I was encouraged. As he walked away, I turned and asked, 'How do I stop
the medicine from working?'

He replied, 'Your partner must say '1-2-3-4 ,' the shaman responded. 'But
when she does, the medicine will not work again until the next full moon.'

I was eager to see if it worked. I went home, showered, shaved, took a
spoonful of the medicine, and then invited my wife to join me in the
bedroom. When she came in, I took off my clothes and said, '1-2-3!'

Immediately, I was the manliest of men!

My wife was excited and began undressing ... 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.