Definitely not. Sexual stories, especially those related to items like crotchless panties, are inappropriate for sharing. It can make others uncomfortable and is not in line with the general standards of good taste and respect in public or private interactions.
In such a situation, it's a sign of a major problem. It might suggest that she has engaged in sexual activities outside of her marriage. Her husband would be devastated, and the relationship would be in a state of crisis. There would be a need for serious communication, but it's likely that the relationship will never be the same again. The trust that was once there has been shattered, and it would take a huge amount of effort, if at all possible, to rebuild it.
No, it is not appropriate at all. Such stories involve private and sexual content that should be kept within the boundaries of a private and consensual relationship. Sharing this kind of story in public violates privacy and is not in line with good social ethics.