An old farmer gives his two sons money to buy a bull. They drive to the livestock market and purchase a magnificent prize bull, but only need half the money, so they decide to head to the brothel.
They tell the Madame they want a really good time with a nice blonde girl and hand over the cash, but they ask to be allowed to take the bull into the room with them in case it gets stolen.
Later, the Madame asks the girl how she got on with the boys:
"The first guy was a bit of a disaster, the second was OK, but the guy in the Viking helmet was f**king magnificent!"