Looking for a story about a boy who found a ring when on holiday with his family. He finds the ring in the water (ocean or lake). When wearing the ring he learns he can control/order people, and he starts to experiment on his sisters. Both sisters know he is using the ring, but they want him to learn to use it.
I have read the first chapters of this story when I first found the story, but do not remember the story name, author or where I found the story. I might have been on SOL, asstr or maybe it is way older and I found it on EWPub. Any help in finding this story is much appreciated.