While parenting your own children is up to you and your partner, it’s tough to know where the boundaries lie when it comes to your friend’s children. There may be times when you just want to give your friend’s child the discipline she needs, while your friend is making light of her daughter’s poor conduct. Still, no matter how rude you think your friend’s kids are, the fact remains: they aren’t your kids. There’s only so much you can do to stop the bad behavior and still continue your friendship with the parent.

You’re friends with this child’s mom or dad, not the child himself. So instead of trying to be cool or talking to the child like you’re his age, carry yourself like an adult. Use your body language to indicate that you are in a position of authority by standing tall, crossing your arms to signal disapproval or simply turning away from bad behavior. If your friend’s kid wants your attention, he won’t get it with negative actions. Psychologist Linda Sonna, author of "The Everything Tween Book," says on Parenting.com that tweens, who can be especially rude, are looking for cues from adults as to how they should act. You can say a lot about your status as a parental figure in the way you carry yourself, without saying anything directly to your friend’s son.

Instead of confronting your friend aggressively by listing her daughter’s “rap sheet," try to engage her in a conversation about parenting. After a behavioral episode by her child, you can express sympathy, saying something such as, “This age is so tough. How is it going?” If you’re sincere, your friend may open up to you about her difficulties with parenting and may even ask for your advice. You can offer strategies that have worked in your own family or suggest books that have helped you with positive discipline. If the conversation isn’t going well, drop the subject for now. Giving her unsolicited parenting advice is likely to strain your friendship.

Though your friend might get testy about another adult disciplining her child, she can’t complain that you’re praising her son too much. When you see your friend’s child doing something well, offer words of encouragement. Even reinforcing his smallest actions, such as praising him when he chooses not to interrupt or when he takes the initiative to rinse a dish by himself, can make a huge difference in his behavior. If your friend’s child starts getting noticed for the good things he’s doing, he’s likely to keep behaving well in the hope that adults will continue giving him positive attention. Your friend might get the hint, too.

As a mature adult, you can ignore your friend’s daughter’s annoying behavior to a point. But if your friend’s child is actually behaving badly toward your children, you have the right to intervene. Make sure, though, that you don’t have a blind spot when it comes to your own kids. Collaborate with your friend to get the whole story. If your friend still refuses to address her child’s bad behavior, then you can tell her (and maybe her daughter) that this would never be considered appropriate behavior in your family. Stop short of doling out punishments to kids who aren’t your own. This scenario may upset your friend, but ultimately the health and safety of your own children should be your priority. If she’s a good friend, she’ll cool down and call you again.