Chastity belt

All the good knights were leaving for the Crusades.

One knight told his best friend, "My bride is without doubt one of the most beautiful women in the world..."

"It would be a terrible waste if no man could have her. Therefore, as my best and most trusted friend, I am leaving you the key to her chastity belt to use should I not return from the Crusade."

The company of knights were only a mile or so out of town when they noticed a cloud of dust approaching.

Thinking it might be an important message from the town the column halted.

A horseman approached. It was the knight's best friend.

..."Hey, you gave me the wrong key!!!"