Two parents want to have sex

Their 7 years old son was in the room, so they tell him to go on the balcony to play with his toys

After the boy leaves they start having fun, after about 10 minutes the husband says:

-We should talk to him while he's on the balcony, i don't want him to feel alone

-Yeah, you're right

So the wife says in a louder voice:

-Honey, what are our neighbours doing?

The son replies:

-Well, Ms.Miller is moaning the lawn, Mr.Richard is washing his car and Jason's parents are having sex

-WHAT?! Honey, how do you know that??

-Because Jason is sitting on the balcony