Clearing the Confusion

Our two kids get things confused all the time. They think that things that apply to them and how they respond to us, also applies with them and other kids. I know it sounds confusing but I will explain...
They know that they canNOT be sassy with adults or talk back, in any way to adults. Well they think that applies to each other. Our son is the worst for it. He was being bossy with his sister and she, understandably, told him, "You're not the boss of me! You don't tell me what to do!"
You should have seen the look on his face. He really couldn't believe it and thought I was going to do something about it.
"Mama! Did you hear your daughter talkin' back to me?" he shouted.
Once I stopped laughing and chocking, I explained that there was no such thing with his sister- that it did not apply to her. He was disappointed to say the least, but I didn't realize until a few minutes later who he was really disappointed with when he referred to me as his daddy's wife.