If you have an impulsive child, a child who can't handle stress, or a child who perseverates on phrases and activities once they're put "in the pipeline," one of the worst things you can say is, "If you do that one more time, you'll be punished." You may find that your child will be irresistibly drawn to do just that, at once -- whether because you've set an impulse in motion, because he can't deal with the stress of waiting for the other shoe to drop, or because he gets stuck on what you've said. Yet sometimes, an ultimatum seems to be what's called for; you can't just let behavior go on forever, yet you don't want to deal the consequence without giving your child a chance.
Instead of specifying one more time, try saying something along the lines of, "I have a number of times in my head, and you're not going to know what that number is. But when you hit that number, you will get a consequence." This allows you to give your child extra chances if he seems to be trying without going back on a threat, and gives your child a little comfort zone to know that he can slip once or twice. Some kids will dislike the uncertainty of it, and for them, this might not be the best technique. But if certainty is more pressure than your child can handle, it may just do the trick.

