I read a coming of age story a long time ago on ASSTR where an older woman teaches a boy about the facts of life. I don't think she was a mother but rather a mentor. I think the story may have had Mentor in the title.
Looking for similar stories / recommendations if anyone read that story.
Adventures of Martha and me by SJR (Santos J. Romeo) ?
Adventures of Me and Martha Jane
My "Wicked Mother" might interest you.
https://storiesonline.net/n/42825/wicked-mother
It's not his wicked mother who teaches the boy. It's the kindly mother next door.
I seem to recall a story about a boy and his best friend who lived next door. I don't remember the exact story but he winds up with being educated by the mother.
That's a story that's been in my head for about a year. Are you reading my mind? If so, be careful.