Having a child of 5 is not a great thing for the parents because they cannot tell each other when they want to have sex out loud.So this couple used secret meanings. They refer to sex as "doing laundry".
So one day, the father wants to have sex and says to the kid, "Tell mommy that I have some laundry for her to do." So the kid goes tell his mother, "Mommy, mommy, daddy says that he wants you to do his laundry."
The mother was quite busy at the time so she says to the kid, "Tell daddy that the washing machine is not working right now." So the kid go and tells the father that the machine is broken.
The father is really desperate and tells the kid, "Go and tell mommy that I really need her to do my laundry...ASAP." The kid goes tell the mother and the mother still say that she is busy.
After an hour or so, the mother is free and wants to relieve her husband. So she tells the kid, "Go tell daddy that I can do the laundry now." The kid goes tell the father. When the kid comes back, he tells his mother, "Daddy said he already used his hands to wash them."