How it happened . . .

This sailor walks into a pub, and draws many stares because his head is
the size of an orange. He walks up to the bar and asks for a beer. The
bartender pours him one, but can't supress his curiosity and asks the
sailor about his head. The sailors story goes like this: he was the only
survivor of a shipwreck, stranded on a beautiful tropical island with
plenty of fruit and fish for him to eat. The only thing was, he was
getting terribly lonely (and horny). One morning, he woke up to a woman
crying. He ran down to the beach, and there stranded at the high tide
mark was this beautiful mermaid. He carried her down to the water and
she told him that she was a magical mermaid and for saving her she'd
grant him his wish. He just couldn't help himself, but asked to have
sex with her. The mermaid explained that it really didn't work like
that, she just had this fish tail and you know, not compatible equipment.

So he said:

"What about a little head?..."