We know what you are doing!

A man and a woman are seated next to each other on a flight. They start eyeing each other up, and both realise 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 sharpeyed stewardess has noticed them, and realised what they are up to, so she humiliates them both by making an announcement over the radio . To the lady and gentleman in the rear toilet, we know what you are doing, and it is expressly forbidden by airline regulations. Now, please put those cigarettes out and take the condom off the smoke detector."