An old man finds a condom in his grandson's apartment and asks: "what it is?".

"It's a condom", replies the grandson sheepishly.

"What do you use it for?", asks Grandpa.

The grandson is embarrassed. So he says: "I use it to keep my cigarettes dry when I smoke in the rain."

Grandpa says: "That's a great idea". He goes to the drug store and asks the pharmacist for a condom.

"What size would you like?", asks the pharmacist.

"Big enough to fit a Camel"