Jon takes his dog for a walk. After awhile he gets thirsty so he ties his dog to a parking meter in front of a bar and goes in for a couple of beers. After he has been there for an hour or so the local policeman enters the bar.
"Whose dog is tied up out front?"

Jon responds, "That's my dog. Is there a problem, officer?"

"Well, she's in heat," says the cop."

"Oh, she'll be all right. It's shady out there."

At this point the policeman is becoming a little upset. "Listen fellow. You don't seem to understand what I am talking about. That dog needs to be screwed."

"Go right ahead officer, I've always wanted a police dog."