A guide dog owner is walking his dog through a park when suddenly the dog stops raises it's back leg and pee's down the guide dog owners leg, the guide dog owner puts his hand in his pocket and withdraws a biscuit, which he then gives to the dog, a bystander observes the incident and approaches the guide dog owner and says, your dog has just peed down your leg, the guide dog owner replies, yes, it's running into my shoe as we speak, the bystander then askss, why have you given your dog a biscuit when he has peed down your leg, the guide dog owner replies, well, I needed to find out where his head was so I could kick him up the arse!