As you parent your multiples (or singles!) learn to tell the difference between childishness and disobedience. Children do childish things. It is born out of immaturity, not defiance. It includes spilling things, breaking things, losing things, etc. Childishness does not deserve discipline. It must be trained and taught into maturity, but it is not the same as defiantly refusing to obey, which is disobedience.
Moms, "be quick to hear, slow to speak, and slow to anger for the anger of man does not achieve the righteousness of God" (James 1:19-20). Moms, as you attempt to judge your child's behavior, be slow to discern if it is childishness or disobedience. Be slow to react or respond. And if it is disobedience, and requires a measure of discipline - be very sure you do allow your frustration and aggravation to push you to punish in anger.