"Stop yelling mom"

Sam just started crawling and is already getting himself into mischief. Because of that, I find myself saying "No, Sam, don't!". I don't yell but those that know me know that my voice is loud and can carry a bit of a punch. So Sam has picked up the habit that when I yell at him he tells me stop with his hand! I don't know if it's "stop" that he's trying to say or "calm down" or "wait a minute" but the hand goes straight up in the air everytime! It takes everything I have to stop from laughing. I don't laugh (at least not on front of him) and I won't. I want my son to obey me when I caution him from doing something where he can get hurt, but when he turns around and puts that hand in the air I can't help but want to laugh. It's the cutest thing I've ever seen. So I wait and at night, in the privacy of my bed, I think of my little boy with his hand in the air and I can't stop laughing.