A redneck goes to his doctor...

...and asks him "Hey doc, I don't want to risk having any more kids."

The doctor says "Well I would suggest a vasectomy, then."

The redneck says "That costs way too much, though. Got any other ideas?"

The doctor thinks for a minute then says, "ok, what I want you to do is, when you get home tonight, put a firecracker in a beer bottle then count to ten."

The redneck looks confused, but trusts the doc, thanks him, and goes home.

Later, he had just finished his beer and had his firecracker ready. He lights it, drops it in the beer bottle then, holding the beer bottle in one hand, counts off the fingers on one hand. "One... two... three... four... five..." he stops and thinks... quickly, he sticks the beer bottle between his legs and continues on the other hand, "six... seven..."