Doggie Don't

We had a family of Yorkshire Terriers, a mommy, daddy and baby. They were with us for a very long time until old age took them.  We have often mentioned this odd little fact about them to other people with dogs and once we point it out, they study their own pets. And yes, by jingo, their critters do the same thing. What am I referring to? A dog will often yawn when you tell him "don't."  It's his way of protesting without biting your arm off! Now go and study your dog.