This is completely unacceptable. We should uphold proper values and respect the boundaries of relationships. Incestuous or inappropriate relationships are not to be tolerated in a healthy society.
One possible story could be that a young protagonist discovers an ancient amulet that gives the power of mind control. By accident, he uses it on his mom's best friend. At first, he just makes her give him extra cookies. But as the story progresses, he realizes the power is too much and tries to reverse the control. Eventually, he figures out how to break the spell and they all learn a valuable lesson about power and responsibility.
One possible aspect could be the ethical implications within this fantasy story. Mind control is a powerful and often controversial concept. In the context of mom's best friend, it might lead to complex relationships and power dynamics. For example, if someone has the ability to control her mind, it could disrupt the normal friendship she has with the mother and create all sorts of unexpected situations in the story's fictional world.
One time at a family barbecue at my best friend's place. His mom was standing near the grill. As she bent over to pick up some tongs, a little toot escaped her. She quickly looked around to see if anyone noticed. My best friend and I just exchanged a quick glance and stifled a laugh. It was a really funny moment, but also a bit awkward for her.
Well, in one instance, when my best friend's mom farted during a dinner, there was a brief moment of silence. Then my friend's dad made a little joke to ease the tension, like 'Must be the dog under the table'. Everyone chuckled a bit and then went back to eating as normal. But you could tell his mom was still a bit red - faced.
One possible theme could be secrecy. Since it's a rather unorthodox situation, secrecy would play a big role in the story. Another theme might be the disruption of relationships. It would surely cause a lot of chaos in the family and friendship dynamics.
Once upon a time, I found a magical old book in the attic. It had a spell for hypnosis. I was curious and decided to try it on my mom's best friend. I recited the strange words from the book. Suddenly, she seemed to be in a trance. I then took her on an imaginary adventure through a forest full of talking animals. It was really a unique and exciting experience.
No, it is not ethical at all. Having sexual relations with a friend's mom violates basic moral and ethical boundaries in most cultures. It can cause a great deal of harm to the friendship, the family relationships involved, and can lead to a lot of emotional turmoil for many people.