A farmer wants to start breeding pigs, so he goes out & buys a bunch. After a few months, he wonders why they aren't procreating - so he goes into town to see the vet. There, the vet tells him that what he needs to do is artificially inseminate them. Not wanting to show his ignorance, he asks the vet how he'll know they've been inseminated properly. "Oh, don't worry" says the vet, "they'll be rooting & wallowing around in the mud something fierce once the deed is done."
So the farmer returns to the farm, loads all the pigs into the truck & drives out to the woods. Once there, he proceeds to screw each & every pig. When he's done, he loads them back into the truck & drives back to the farm to finish his chores.
The next morning, he looks out the window to see if the pigs are rooting around, but no such luck. So he loads them back into the truck & goes back out to the woods where he screws each pig - twice this time. He loads them back up & returns to the farm just in time to finish up the days chores.
The next morning he looks out the window, but still no rooting & wallowing. Frustrated, he loads them all back into the truck and drives back out to the woods where he spends all day shagging each & every pig three or four times. Exhausted and spent, he loads them up & returns home so late that all he can do is collapse into bed, chores unfinished.
The next morning, he's so tired & sore he completely over sleeps & can't even get out of bed, so he says to his wife "maw, look out the window. Are the pigs rooting around in the mud yet?" She looks out the window and replies "No, actually, they're all in the back of the truck... and one of them is honking the horn."