At dessert that evening, I told him he could have ice cream and one cookie. Munchkin promptly grabbed both a cookie and a piece of fudge. We made him put back the fudge, even though he insisted it wasn't a cookie. After he had polished off everything, he tried again to grab some fudge. I said "no," and he started to protest. It's Christmas, so I said, "Give me your best pathetic look."
Munchkin's little pouty face dropped another notch and he lowered his chin slightly, doing an absolutely perfect "pathetic little boy who needs some fudge" look. Everyone at the table cracked up, but Munchkin held the look, motionless until he got his fudge. Then he broke out into a big grin. It's scary how well he can do that.