This guy is nearing the end of his senior year in highschool,
unfortunately he still has to share a room with his younger brother
who is about 5 or 6.
One night, he decides to bring his girlfriend home for a little
fun. They have bunk beds and the guy notices that his little
brother is already asleep on the lower bunk, so he and his gal
climb up to the top bunk.
As you might expect things start to heat up. The guy remembering
that his little brother is sleeping below so he tells his
girlfriend to whisper,"lettuce" if she wants it harder and "tomato"
if she wants a new position.
Lettuce, tomato, lettuce, tomato, lettuce, lettuce," it
sounds.
Then the little brother chimes in, "Hey, would you guys stop
making sandwiches up there, you're getting mayonaise all over my
face."