Sharing such stories is highly inappropriate. It involves private and often sexual content which is not suitable for public discussion or sharing. It violates the privacy and dignity of individuals.
It's not ethical at all. Imagine if someone was spying on your mother's stories without her knowledge. It's an invasion of personal space and can cause a great deal of discomfort if discovered. Respecting privacy is a fundamental principle in a civilized society.
Perhaps the story could involve the young man being new to the neighborhood. The mature mom, being kind-hearted, welcomes him and introduces him to the local community. As time passes, they collaborate on a community project, for example, a neighborhood garden, and through this they build a unique bond based on mutual respect and shared interests.
One common theme is self - discovery. Many mature moms find time for themselves after years of focusing on their families and discover new hobbies or career paths.
It is highly inappropriate in a traditional family and social context. Such an item is considered private and not something that should be casually brought into a family home where it may be discovered by others, especially children or those who may be offended by it.
One common theme is sacrifice. Mature moms often sacrifice their own needs and wants for the sake of their children. For example, in many stories, a mom might give up her career dreams to take care of her family. Another theme is wisdom. They usually have a lot of life experience which they use to guide their children. Like in some traditional stories, the mom always gives the best advice when the kids are in trouble.
It's not really possible to say it's common or not in a general sense. Everyone's sexual exploration and comfort with certain products is very individual. Some mature moms might be more open to exploring new aspects of their sexuality, while others may not be interested at all.