A man and a woman are seated next to each other on a flight. They start eying each other, and both realize they want to do the same thing. He slips a condom out of his pocket, and she looks delighted.
Rear toilet? He suggests. Five minutes, she agrees and goes off. He waits five minutes, then goes and slips in there with her. Right, get that condom on, she says. Soon, they are both sighing with pleasure.
But a sharp-eyed stewardess has noticed them, and realized what they are up to. So, she humiliates them by making an announcement over the PA system.