Be straightforward with your child.
Honesty is the best policy when talking to your child, says board-certified family medicine physician Deborah Gilboa. “If this child has a behavior that rubs off on our kids but isn't dangerous, then we can level with our kids.” She suggests giving your kid this ultimatum: “Your friend X speaks disrespectfully. I've noticed that, after she visits, you pick up this habit for a while. If you'd like to continue to hang out with X, you're going to have to stop absorbing this behavior.” Annoying quirks can rub off on your kid, and by calling it out, you alert your little one to stop the sass after his friend heads home.