One day, while doing door-to-door market research, this guy knocks on a door and is greeted by a beautiful young housewife.
He's inquiring about a particular petroleum jelly product to see how it's being used, and by whom.
"Hello," he starts, "I'm doing some research for a petroleum jelly manufacturer. Have you ever used the product?"
"Yes. My husband and I use it during intercourse," she answers.
The researcher is stunned by the blunt reply but quickly regains his composure.
"Um, er... I admire you for your honesty," he continues.
"Can you tell me exactly how you use it?"
"Sure, we put it on the doorknob so the kids can't get in."