The automatic flush systems are really hard on young children. They are way TOO LOUD and they trigger very easily. We had this problem and it didn't go well . . so I think maybe the thing to do is make a "visit to the ladies room " -- but not to use it. Go in the stall and watch the swirlies. Make motion happen, so the thing goes off and let her watch it. You can laugh, clap when the show is over, whatever . . .but definately talk about it. When you're sitting on it, and it starts to go, there's also a wee rush of cool air, so that can be kind of startling to a youngster. . . If you can make an "educational visit" out of it, maybe you can defuse the fear that goes with the thing, and then maybe it will be "fun" to ride the wild beast of a toilet. :-)