So, we're potty-training here. Katherine is ready for it -- she's very interested in matters scatological, wakes up dry, and announces when she has dirty/wet diapers. Claire likes to sit on the potty, but she is clearly not as interested in it as Katherine, and not as aware of when she is going in her diaper. If she were a singleton, I wouldn't even try to train her for a little while.
Problem is, she insists on doing everything that Katherine does. Right now, I'm sitting in the kitchen with them, doing the bare-bottomed thing. We did it yesterday morning, and Katherine peed in her potty, while Claire peed on her chair. Today, Katherine has peed twice(!), while Claire hasn't done anything so far. When Katherine goes, I get really excited and praise her, and then I dish out a piece of Halloween candy. Since they are old enough to understand about fairness, this causes a giant problem, because Claire wants a piece too.
On the one hand, it seems wrong to give her a piece, because it's a reward for using the potty, which she is not doing. On the other, not treating her just causes a tantrum, and I worry she will transfer the frustration to the whole potty process. But then, she is at least sitting on her potty enthusiastically, which is a good thing, and is all I should expect of her at this point. I don't really expect Katherine to go exclusively in the potty either, for that matter -- I'm just working on getting her going there on a regular basis right now -- but if Claire goes, it's really just a matter of good luck.
I'm compromising by giving Katherine two pieces for each potty usage, and Claire gets one "because you sat on the potty so well!". However, it's an inherent problem of having multiples, the conflict between fairness and individual maturity. I suspect future versions of this conflict won't be so easily solved with a few extra M&Ms.