Little Johnny attended a horse auction with his father. He watched as his father moved from horse to horse, running his hands up and down the horse's legs, rump, and chest. After a few minutes, Johnny asked "Dad, why are you doing that?" His father replied "Because when I'm buying horses, I have to make sure that they are healthy and in good shape before I buy". Johnny, looking worried, said "Dad, I think the postman wants to buy mum".