Neighbour: Blow him back

Warning !! For adult only...

One night, a young boy heard noises from his parent's bedroom. It was hard for him, but he went back to sleep. The next night he heard the same noises, but once again fell back
asleep. Finally, on the third day that he was woken up by his parents, he decides to see what the heck they are doing. So he walks up to his parents room, and sees his mother on top of his father. She is moving up and down on top of him, and they both are making
grunting noises. He has no idea what is going on, and decides to go back to bed.
The next morning the boy tells his mother about how they woke him up, and what he saw when he went to see what they were doing.

Finally, he asks what was going on. His mother decides he is too young to learn about sex, so she tells him that since his father is getting old and fat, she has to jump on
top on him to keep him thin.

"But mommy," the boy exclaims, "That won't work, cause everyday when you go to work, the next door neighbour comes over and blows him back "