Most of the time? Nothing. Most sibling squabbles are healthy and harmless --they're how kids learn to problem-solve and relate to others. So stay back, unless the bickering gets physical. But when you just can't take it anymore, try telling them:

* I can't wait to hear how you solve this. Go into a room and don't come out until you agree on a solution.

* Since you're not having fun, please help me fold laundry.

* You can either stop fighting or pay me to listen. I'll take a quarter for each scream, please.

* Looks like that toy needs a time-out --it made you fight! We'll get it out again later.

* You guys should be proud of yourselves! You played together for 20 minutes before you started arguing. Let's celebrate with (insert a treat here that they can't possibly fight over, like two equal amounts of chocolate milk in two identical glasses).

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