Little Jimmy came home from school one day and walked into his parents bedroom, where he saw his mom and dad going at it.
Without his mother seeing, Jimmy's dad gave his son a thumbs up and kept on going. The next day Jimmy's father comes home from work and walks into his son's room to see what he was up to.
When he walked in he saw Jimmy had his grandmother tied to the bed and was doing unimaginable things to her..His father yelled "JIMMY WHAT ARE YOU DOING?"
Jimmy replied....."It's not so funny when its YOUR mom, huh?