First of all, it's an extremely awkward situation. If it was an accidental encounter, it's important to communicate your discomfort. You could talk to your mom privately about it, without accusing her friend. Just say that you felt violated in a way and ask her to ensure it doesn't happen again. Maybe it was a misunderstanding, but your feelings are valid.
You could laugh it off. I know it's easier said than done, but if you can find some humor in the situation, it might make you feel less embarrassed. Maybe say something like 'Well, that was an unexpected sight for you!' in a light - hearted way to break the ice and show that you're not too bothered (even if you are a bit).
First, you need to stay calm. Have an honest conversation with your friend to understand exactly what happened. If it was an accident, like in a situation where there was a misunderstanding at a pool or beach, you may need to set clear boundaries. For example, make it clear that such a situation should never happen again. And also communicate with your wife to see how she feels about it.
One possibility is that there was a miscommunication. For instance, if there was no proper notice given before entering a room. Also, she might have been distracted and not thinking clearly about privacy. Or perhaps in some cases, she has a different cultural background where privacy norms are not as strict as yours.
You should immediately stop sharing such stories. Then, have a serious conversation with your kids about privacy and what is appropriate. Explain that these are private matters and not for sharing or seeing.
If this has happened, it can be really uncomfortable. First, you should talk to your mom about it. Let her know how you feel and that it made you uneasy. Maybe it was an accident, but it's important to communicate your discomfort.
Just be calm and respectful. Avoid making her feel self - conscious. A simple 'Sorry, honey' and then give her some privacy if she wants it.
The wife should immediately cover up and ask for privacy. The friend should respect that and leave the area as soon as possible. Then, they both need to have an honest conversation later about how it happened and how to move forward without any awkwardness.
The friend whose son was involved should have a calm conversation with the mother. Let her know that such topics are unacceptable. The mother should also take steps to educate herself about appropriate conversation topics with children. For example, she could read some books on child - friendly communication. And the mother needs to be more cautious about her language and topics when interacting with the son again.
Stories like this often happen during childhood or adolescence. For example, when you're getting out of the bath or changing clothes. The first step to dealing with the embarrassment is to accept that it's a normal part of growing up. Everyone has some awkward moments with their parents. Also, you can focus on building more positive and mature relationships with your mom so that this incident becomes just a small memory in the past.
Just try to forget about it as much as possible. Don't keep replaying the scene in your head. Focus on other things in your life.