Q: I’ve known my ex since high school. We were married 20 years and have two teenage boys who live a week with me and a week with him. He recently started dating a woman who is only seven years older than our oldest son.

Evidently, she dresses like someone seven years older than my oldest son and my son tells me he’s embarrassed to have his friends over because they make comments about “Dad’s hot girlfriend.” He’s used the word “slutty,” which is concerning. My son has asked me to talk to his dad, but I don’t know what to say. What’s good ex-etiquette?

A: That’s a tough one. Normally I suggest parents speak directly to each other when there is a problem at either home. Asking a child to pass on information puts too much pressure on them and if they are afraid the information will upset the parent, they censor the message.

For example, “Mom told me to tell you that Tiffany dresses like a slut.” Mom didn’t say that, but if your son is too afraid or too embarrassed to say anything it becomes Mom’s idea. That’s when I hope co-parents have the good sense to check in with each other to clarify what’s true. Although most parents think their child would never lie to them, sometimes they do.

That said, this particular situation may be one of the few times I suggest your son take this up directly with his dad. Since he is a teenager and old enough to even be embarrassed, if he talks to Dad directly it would allow them to cultivate their own relationship without using Mom as a buffer.

Now, how to prepare your child:

May I suggest you don’t say, “Tell your dad, not me.” Doing that leaves your son to his own defenses. You already know he doesn’t know how to handle the situation. That’s the reason he went to you in the first place. Asking him, “Would you like to talk to Dad about this?” is a good way to open a dialogue.

Be careful not to badmouth Dad or Tiffany. Let your son take the lead and together brainstorm for the proper words to broach the subject.

Help your son to mentally clarify exactly what he wants Dad to do. Does he want Dad to break up with Tiffany, or does he just want her to dress differently when his friends are around? When your son has a clear idea of exactly what he is requesting, that’s when it’s time to talk to Dad.

There’s a fine line between running defense for your child and helping him to feel comfortable discussing a sensitive subject with his other parent. Set the stage by being honest and straightforward and modeling respect for your child and his other parent.

Jann Blackstone is the founder of bonusfamilies.com.