Johnny was playing outside when he really had to go to the bathroom. He runs in and his grandma was about to take a shower. He looks at her crotch and says, Whats that? She says, Well, it's a beaver, Johnny.
The next day the same thing happens, only his mom is taking the shower. He says, Mom I know what that is. It's a beaver, but I think grandma's is dead because it's tongue is hanging out.