So Timmy, about 10 years old, said he wasn't feeling well so he walked him self home from school.  He put the key in the keyholeand sees dad has mom bend over on the couch giving it to her. The kid freaks out and runs upstairs. The parents are like oh my god.

The next day Timmys dad comes home from work. Puts the key in the keyhole. He opens the door and sees Timmys got grandma over the couch just railing her.
The dad said "Timmy what the fuck?""
Then Timmy said "YEAH ITS NOT SO FUNNY WHEN ITS YOUR MOM IS IT?"