A bloke was marooned on a remote island after a shipwreck. The only other survivor was a small terrier. The only other occupants of the island were a small flock of wild sheep.

After a few weeks the chap's natural manly appetite was getting the better of him. He'd noticed that one of the sheep was quite placid, so temptation got the better of him. But no sooner had he dropped his trousers that the terrier started to bark incessantly and dash frantically round his legs, completely frustrating his intended, er, enterprise. Over the days, this happened again and again and the poor fellow never got his wicked way with the ewe.   

Months later there was another shipwreck just off the island. The only survivor was an absolutely beautiful young woman, badly injured and half-dead as yer man dragged her on to the shore. For weeks he tended to her wounds and looked after her until she was fully recovered. One day she said to him, "I'm so grateful to you for saving my life and restoring me back to health. I'd like to return the favour - I'll do anything you ask...and I do mean ANYTHING..."

"OK," he replied, "Would you just watch the dog for ten minutes?"