The Service Dog

A blind man was out walking with his service dog when suddenly the animal paused and wet the man’s leg.
Bending down, the blind man stretched out his hand and patted the dog’s head. Having watched what happened, a bystander said, “Why are you patting him? That dog just peed on your leg!”
“I know,” said the blind man, “but I gotta find his head before I can kick his behind.”