This guy goes into a bar with a monkey on his shoulder and orders a beer and a whiskey, he takes a sip of Guinness and gives the monkey the whiskey. The monkey knocks back the whiskey. The guy then punches the monkey square in the face knocking it to the floor. The monkey gets up moves to the front of the guy, unzips his trousers and begins to perform oral  on him, when finished the monkey slowly climes back on to the guys shoulder.
The Barman and another customer had been watching the whole event.
The barman then approaches the guy and asked him if can he have a go with his monkey. The guy says no problem and places the monkey on the barman's shoulder the barman sets up the drinks as before takes a sip of the Guinness and gives the monkey the whiskey. On finishing the whiskey the barman punches the monkey who proceeds to carry out the  act as before.
At this point the other customer comes forward and says in a shy embarrassed manner "Excuse me sir, but I have been watching you and your monkey, do you think it would be possible for me to try?" Once again being an obliging chap the guy says "No Problem" the customer then says "Great but there's just one condition," "What's that enquires the guy". The customer responds, "You must promise not to hit me as hard as you hit the monkey."