For example, this one:
A boy walks in on his grandma taking a shower, points to her crotch and asks what that is. She thinks up a quick answer, and says "That's my beaver". The next day, the boy walks in on his mother taking a shower, points to her genitalia and says "Mommy, I know what that is. That's your beaver". She asks him how he knows that. He says "Grandma told me. But I think her beaver is dead. Last time I saw it, its tongue was hanging out."
?
A boy walks in on his grandma taking a shower, points to her crotch and asks what that is. She thinks up a quick answer, and says "That's my beaver". The next day, the boy walks in on his mother taking a shower, points to her genitalia and says "Mommy, I know what that is. That's your beaver". She asks him how he knows that. He says "Grandma told me. But I think her beaver is dead. Last time I saw it, its tongue was hanging out."
?