A bloke gets marooned on an Island with his faithful companion his dog and a sheep. anyway nights go by where they are sitting by the shore and looking out at the moon on the horizon and one night the bloke starts getting frisky and looks at the sheep, the dog sees this and starts snarling, this go's on for a week, one night the bloke sees something bobbing on the horizon and swims out to see what it is, finds out its a woman and swims back to shore clutching her around the waist.
That night he introduces her to their ritual of sitting at the shore and as the evening wears on the bloke starts getting realy frisky and turns to the woman and says...will you do me a real favour, he ask her...she says whats that then...will you take the dog for a walk he replies.