The old professor started each lecture with a dirty joke.
After a real objectionable example of that one day, the
female students got together and decided that next time,
when this happens again, they will all walk out in unison.
The professor got wind of this plot. Next morning, after he
entered the lecture hall, he said: “Good morning! Have you
heard about the shortage of prostitutes in Alaska?”
Now all the female students stood up and headed toward
the exit.
The professor continued: “Oh, ladies, please wait, the plane
to alaska doesn’t leave until tomorrow!”
“We know, but it takes all of us and a whole day to carry your mom” replied one of the students