A bloke is out walking his dog and gets talking to another bloke
He says "hold up.. gotta let the dog off the lead.. he needs to take a leak" and lets the dog off and they carry on chatting
the dog walks up the nearest wall... sniffs it... then goes up on his two hind legs and walks up to the wall.. puts his front paws on the wall and takes a slash!
The second bloke looks on amazed.. and says "Wow... that's the oddest thing... how long has he done that?"
and the dog owner shrugs and says "since a wall fell on him!"