My ds2 (3.5) was just very very cheeky to me. He then stormed into his brothers room and slammed the door. I was just about to go and retrieve him for a session of sitting on the naughty stair when I heard ds1 (6.5) say "You shouldn't talk to Mummy like that Xxxx, it's not nice".
Where did that come from !!! He sounded so grown up.
I then went downstairs and 5 minutes later they come down the stairs, ds1 in front saying "Xxxxx has got something to say to you". Ds2 then comes and says "Sorry Mummy". And we all have a big hug.
Maybe he'll be a diplomat when he grows up.