It depends on how you look at it. In a consensual BDSM context, where 'submissive' is a role that is freely chosen, and all safety and communication protocols are in place, it can be considered ethical. But if there's any coercion or lack of clear understanding, it's not. Also, sharing such stories publicly might violate the privacy and dignity of those involved, which makes it a gray area ethically.
The ethics of first time submissive sex stories is a complex matter. Some might argue it's unethical as it involves a power dynamic that could potentially be exploitative. However, if both parties are fully consenting adults who have thoroughly discussed boundaries and expectations, it could be seen as an exploration within the realm of consensual sexual relationships. But in many cases, these stories can also objectify and dehumanize individuals, which is not acceptable in an ethical society.
On one hand, if the first time submissive sex stories are based on real experiences and the people involved were in a healthy, consensual relationship, it could be argued that they are a form of sexual self - expression. On the other hand, society often has moral and ethical standards that frown upon extreme power imbalances in sexual relationships. So, overall, it's a very subjective topic and can't be simply defined as either ethical or not without considering all the factors involved.