This man and this woman share a bunk bed with their son. The man and woman sleep on the top and the kid sleeps on the bottom. One night when the kid is asleep, the parents climb to their bed. The man says to the woman, "Say ham when you want it harder, say cheese when you want it softer."

All through the night the kid hears, "HAM, HAM, HAM, cheese, HAM, HAM, HAM, cheese!"

When the kid wakes up the next morning, he tells his mother, "Mommy, you got to stop making those ham and cheese sandwiches at night cause I end up getting mayonnaise all over me!"