There's a young boy who is scared by thunderstorms, and when one comes around he asks his sister if he can sleep with her so he wont get scared. One week, the weather report looked grim, and the boy slept with his sister each night.
On the Thursday night, the sister brings a boy home. To not let her brother figure out what the two are doing, she uses "Lettuce" for faster and "Tomato" for slower. This goes on for a while until the boy goes,
"Will you PLEASE stop making sandwiches? You're getting your mayonnaise all over me!"