A man enters a bar with a crocodile on a leash and a frying pan.
"Bar-tender, can I get a free beer if I put my Willy on the croc's teeth and hit it with the pan on the head?!"
'Sure, show us!'
The man lays his Willy on the crocodile's teeth and gives the croc a firm blow to the head... nothing happens. He puts everything back and enjoys his beer.
After having drunk 4 free beers he asks to the other people in the bar: "Someone want to earn a free drink and try it?"
One man in a leather pants steps forward and replies: "I do, but promise me to not hit me too hard with the frying pan please"