On his 65th birthday, a man received a gift certificate from his wife. The Groupon 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, the man 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 powerful medicine. Take only "that much", 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 so eager to see if it worked so he went straight home, showered, shaved, put on some music, took "that much" 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 so excited she began ripping off her clothes, and then she asked, "What's the 1-2-3 for?"

And that is why you never end your sentences with a preposition, because you could end up with a dangling participle.