Husband and wife are at it in their bedroom, when the man notices that their son is at the door, watching them, with shock and disgust on his face. He runs off. The dad follows his son to his room to talk to him. He opens the door and sees his son banging grandma.
The son then turns to the father and says, "It's not so fun when it's your mom, is it?"
The son then turns to the father and says, "It's not so fun when it's your mom, is it?"