My 5-year-old just emerged from bathroom, after a session of potty-training my 2 1/2-year-old. On a whim. And it worked. She then proceeded to award him his chocolate (at his request), praising him endlessly. After that she had her first go at brushing his teeth, and you know what? He wasn't wiggly for her.
Oh, and she also taught him to count by 10's this week. And his letter sounds are coming along nicely, too, thanks to Emma.
So I suppose this is yet another perk to having more than one child. Now remind me what I'm supposed to be doing?