"A farmer buys several pigs, hoping to breed them for ham, bacon, etc.
After several weeks, he notices that none of the pigs are getting pregnant. He decides to call a local vet for advise. The vet tells the farmer that he should try artificial insemination.
The farmer doesn't have the slightest idea what the vet means. Not wanting to display his ignorance, he only asks the vet how he will know when the pigs are pregnant. The vet tells him that they will stop standing around, and will instead, lay down and wallow in the mud when they are pregnant. The farmer hangs up and gives it some thought. He comes to the conclusion that artificial insemination means he has to impregnate the pigs himself. So he loads the pigs into his truck, drives them out into the woods, has sex with them all, brings them back home and goes to bed.
Next morning, he wakes and looks out at the pigs. Seeing that they are all still standing around, he concludes that the first try didn't take, and loads them into his truck again. He drives them out to the woods, bangs each pig twice for good measure, brings them back and goes to bed.
Next morning, he wakes to find the pigs still just standing around. One more try, he tells himself, and proceeds to load them up and drive them out to the woods. He spends all day shagging the pigs and, upon returning home, falls into bed.
Next morning, he can't even raise himself from the bed to look at the pigs. He asks his wife to look out and tell him if the pigs are laying in the mud.
"No" she says, "they're all in the truck and one of them's honking the horn."