"Oh stewardess! Are there any sharks in the ocean below?" asks a little old lady, terrified.
"Yes, I'm afraid there are some. But not to worry, we have a special gel in the bottle next to your chair designed especially for emergencies like this. Just rub the gel onto your arms and legs".
"And if I do this, the sharks won't eat me any more?" asks the little lady.
"Oh, they will eat you all right, only they won't enjoy it so much".