Yes-woman with a twist

You must have dozed off. You are in your favourite spot on the beach a few minutes away from your home, strangely secluded by the rocks and bushes for such a crowded place and you hear voices suddenly, from mid-sentence, just feet away from you. The young man and the woman talking are clearly oblivious to your presence, the former sounding almost unpleasantly exhilarated and the latter borderline tearful. "Look, I don't know what the fuck happened to me, I really don't", the woman half-sobs. "I don't want to be doing this, I swear, I don't know why I am!! I don't know why I'm obeying you, why I've been obeying my stupid brother, why I've been obeying everyone!!"

You look up carefully and barely manage to suppress a gasp. The woman is fully naked and she is fingering herself furiously, hidden only by the thin cover of a bush from all the beachgoers and not hidden at all from you. The man in swimming trunks is pulling his t-shirt over his head. "You keep doing this", he says. "Get on all fours if you want to be lower down. I'm going for a swim". You freeze in place as he walks past you seemingly not even checking to see if his command was carried out. It was - you see the woman drop on all fours (or threes rather as one hand is busy between her legs) as her companion walks past you. As soon as he is a safe distance away, you roll to raise yourself onto your knees. The woman still does not notice you, masturbating furiously... And... Is she sobbing? Yes, she definitely is.

After throwing a glance towards the sea to make sure the male figure is not looking back, you get up. Your shadow falls into the woman's field of vision and she squeals pitifully but does not stop what she is doing. Instead, she awkwardly turns to be able to crane her neck to see you, still fingering herself all the while. "I'm sorryyy!", she wails in a suppressed voice. "I cannot..." Her reaction, the combination of clearly true desperation (nobody is such good an actress) with the continued masturbation and what you have overheard earlier tell you what's going on... Improbable as it is, it is the only explanation. "It's okay, you can stop", you hear yourself say... And she does, pulling her hand away from between her legs and collapsing onto the sand, panting heavily. You will need to make sure, of course, but somehow, some way, she truly seems to be doing whatever she is told.

As you bend over to get a water bottle out of your beach bag and pass it to her, your mind is racing. Clearly everyone who has figured her condition out has been taking advantage of her. And you have to say you want to do the same... In a sense, at least. You do not want to exploit her, you are not that kind of person, but an opportunity is clearly presenting itself for you to be able to tell someone what to do... And unlike with the people she encountered previously, it is not her that you want to be humiliated and (within reason, of course) hurt as the result of that.

It is yourself.