Joke- coming of age

A little boy is terrified as he walks in on his parents having sex. Upon walking into the room, he instantly begins to cry and yells at them to stop fighting.

The father tries to defuse the situation by laughing and assuring his son that they were ok. He wasn't hurting his mommy. They were both just pretending to wrestle.

The kid calms down and daddy tells him to go back to his room and he'll be there in a few min to tuck him back in and tell him a nice bedtime story, etc. With that, the kid turns, takes his bankie and his teddy bear back to bed.

A few min later, winded and satisfied, daddy makes his way down the hall to his son's room and is mortified at what he walks in on.

He walks in on his son having full sexual intercourse with his grandmother. Father gasps and the son stops in mid stroke, looks up at dad and says, .."see? It isn't so funny when it's happening to *YOUR* mommy, is it?"