One day little Timmy walked into his parient's bedroom. He soon found his mom bent over the dresser and his dad going at her from behind.

The dad looked over at Timmy, winked, and gave a little giggle. Timmy walked out the room.

The next day the dad walks into Timmy's room, to see Timmy going at it with his grandma bent over the dresser.

The dad looks at Timmy and screams, "What the hell are you doing?"

Timmy says, "It's no so funny when it's YOUR mom, is it?"