Making Cakes

A couple decide to chance it and
have sex in the living room while their toddler naps.
The child wakes up, and walks in on them.
"What are you doing?"
Flustered and embarassed the mother says, "We were making cakes!"
That answer seems to satisfy the child,
and nothing more is said about it.
Several weeks later the parent attempt to go for it in the living room again, while the child naps.
This time they are successful.
The child sleeps right through it.
When the child wakes up, he goes into the living room to play.
Several minutes later he approaches his parents and says, "I know what you guys were doing!
You were making cakes!"
The parents are shocked..."How did you know that?!?!"
The child says, "I licked the icing off the sofa."