A man from the IRS knocks on a door and see it opened by a little boy. The man asks the boy where his mother is. 'She's in the backyard,' the boy replies, 'screwing the goat.' 'Young man!' the man exclaims. 'You should be ashamed, making up stories like that!' 'But it's true,' the boy says. 'Come in and I'll show you.'
So the taxman follows the little boy to the back of the house and looks out a window into the yard where, he is horrified to observe a woman having sex with a goat. 'That is sick!' he says, turning to the boy. 'Don't you think that is perverse?' And the little boy replies, 'Naaaaaaaaah.'