MERMAID SEX

This guy went into a bar and ordered a beer. He happened to look down the bar and see a man sitting there with a head the size of a cue ball. So he walked down and said to the man, “Excuse me sir, I don't mean to be rude but I noticed you have a small head. Is this a birth defect?” The man said “No, I got this in the war. My ship was torpedoed by the German's in WWII. I was the only survivor on the ship so I swam to shore. One day a mermaid swam up to me and said she would grant me three wishes. For my first wish I wanted to return to the U.S. The mermaid granted that wish. My second wish was to have all the money I would ever need. Wish granted. My third wish was to have sex with the mermaid. She said, ‘I can't grant that wish because mermaids can't have sex.’”
So I said, “How about a little head?”