Perhaps the mom's friend is an artist and the mom has been secretly taking art lessons from her. The son catches them in the middle of an art session at home. He is shocked at first to see his mom doing something so different. As he learns more about it, he realizes that his mom has a whole new side to her and he starts to support her newfound hobby.
A plot might be that the mom's friend is an old acquaintance who has some news about the family's past. The son catches them talking about it, and it leads to a discovery of family heritage. The son at first is a bit startled to see his mom with this person he may not know well, but then becomes interested in what they are discussing.
I'm not sure which specific'son catches mom and his friend story' you are referring to. There could be various interpretations. Maybe it's a story about a son witnessing his mom and her friend doing something unexpected like a surprise party preparation, or perhaps some innocent activity that just seemed strange at first sight.
Perhaps the son was playing a game of hide - and - seek and in a panic, hid in the lingerie drawer not realizing how inappropriate it was. When his mother opened the drawer, she was quite surprised to find him there.
Another motive could be revenge. Maybe he has some grudge against the son and he thinks blackmailing the mom is a way to get back at him. He figures it will cause chaos in the family and make the son unhappy.
One'mom catches son' story could be when the son was secretly eating a whole box of cookies before dinner. Mom caught him with cookie crumbs all over his face. Another could be the son trying to dye his hair without permission and mom walked in on him mid - process.
The son can quickly cover up and then be honest about his embarrassment. He might want to ask his mom for some privacy and then later have a conversation about how he'll be more careful about privacy in the future.
He may immediately offer help. For example, if it looks like his mom has fallen asleep uncomfortably on the couch, he could get a blanket to cover her or adjust her position gently.
A possible plot could be that they are driving to a big city for the son's college interview. The mom is trying to give him confidence while the son is a bit worried. During the drive, they might have an argument about his future plans but then make up later.
Well, possible themes might include cooperation. The son and his friend are working together, so that could be a central idea. Also, persuasion might be a theme, as they are 'forcing' the mom in some way, which probably involves trying to convince her of something. And there could be a theme of growth or change, perhaps the son and his friend learn something from their interaction with their mom, or the mom changes as a result of their actions.
One common 'mom catches son and sis' story could be when they are up to some innocent mischief like trying to bake a surprise cake for her without permission and making a huge mess in the kitchen. Mom comes home early and catches them covered in flour and with ingredients all over the place.
Sharing such stories often involves inappropriate and unethical content, so I can't provide relevant stories.