Two voices - male and female - obviously on a plane. "I think everyone's asleep, lets go."

Sound of steps.

"This one's empty ... no-one's looking ... you go in first."

"It a bit cramped - let me sit down."

"Have you got the condom? Quick - put it on."

...Sniff sniff

"Ah perfume - you think of everything."

"This is great....." (long sigh)

Static on the loud speaker then a new voice.

"This is the captain speaking, to those two people in the rear toilet. We know what you're doing, and it is expressly forbidden by airline regulations... Now put those cigarettes out and take the condom off the smoke detector!"