Say the alphabet backwards

I've been practicing pointing out parts of the body and naming them for Xander. He definitely knows "ears" and "belly button", or at least he points to the right part of the body if you say the words. When I say "nose", he points at my nose. I keep trying to get him to point at his own nose, but no joy. How's he ever going to be able to take the field sobriety test if he can't do this...I kid.