Not 2 days ago, she had been a simple serving girl, working on passenger ships as they made their way between islands. All that changed when a storm tossed her overboard. She had no idea what had become of the ship, whether or not it had reached its destination safely. Nor did it matter. All that mattered was that she was now a prisoner of the mermaids. They kept her in the water up to her neck, her arms bound above her to the underside of a post coming up out of the water on a diagonal, the mast of a long sunken ship. Even if she cold escape from the ropes, the inlet she was in was surrounded on all sides by a sheer rock wall. She had no idea how far she'd need to swim to reach land she could climb onto, and in her currently weakened state, she'd never even make it to the mouth of the inlet without drowning. Not that she was weakened by starvation or sleep deprivation. Her captors provided her with food, fresh water, and their torment of her left her so exhausted sleep was easy even in this position. Of course, even if she did have the strength, in the murky water, she had no clue whether she was being guarded at this very moment. The answer became clear when the previously mentioned torment started again.
She felt a slight feathery sensation as one of the mermaids swam past her back, lightly brushing her with its tail fin. "Please, no more" she thought to herself, though she knew more was exactly what was in store for her. Another tail brushed her feet, and she lifted them up, though she knew that wouldn't stop them if they wanted to tickle her there. Her sides and armpits were tickled much the same way. Finally, after the teasing continued for a bit, the real torture started. A pair of hands grabbed her ribs, and began to knead them. With renewed strength, she began laughing and thrashing in the water, but her tormentor was able to keep perfectly still, using strong hands to keep her torso in place. Taking advantage of her stationary torso, another mermaid (or perhaps even the same one) used the very tip of her fin to tickle her captive's helpless bellybutton, which she couldn't move away no matter how hard she tried.
Next a pair of hands appeared at her pits, held taut by the ropes holding her up. Somehow, they were just as smooth and hairless as they had been when she went overboard, and it made this even worse. At first, the nimble fingers just skittered up and down the hollows, which tickled unbelievably in and of itself. But then the hands started scratching. She had quickly learned that mermaids have claws that are quite sharp, but also the dexterity to apply them just right, utilizing them for maximum ticklishness without rending the soft flesh they tormented. And torment they did. Every pass they made drove her to the brink of ticklishness madness. They were slightly curved, which means the effect was lessened as the ran back up her pits, but even that tickled something fierce. And all the while the hands at her ribs and tail at her bellybutton continued their task.
Next followed the moment she was dreading. She felt two slimy stands of seaweed wrap around her ankles and pull, stretching her body out. At first they had used their hands to hold her ankles, but soon they adopted this tactic. Maybe it was a new idea they were trying on her, maybe they always ramped up the tickling over time, it really made no difference. All that mattered to her was what followed. Another tail began to torment her feet, the feathery fin sending electric pulses throughout her body. Her feet had been separated by exactly the distance needed for one tail to tickle both, each foot getting one side of the fin. Even when she curled her toes, it seemed to effortlessly slip under them when it passed up her foot, and tickle the soft and sensitive spots. Despite how badly it tickled, she much preferred it to the hands that would inevitably come next, but all too soon did she feel the curved claws running up and down her feet. At first, it was only one, slowly dragging up and down. Already it was unbearable. Then a claw appeared on her other foot, it too just slowly going up and down. Soon, two claws were gently scratching each foot, tickling even worse. Just slowly going up and down the ticklish flesh, the down movement making everything go black for a second as it tickled her to insanity. Then the real torment of her feet started. Apparently two different mermaids were tickling her feet, as after one pair of claws passed up her feet, tickling from the heel to the arch to the ball and just below her poor toes, another pair ran down from the base of her toes to the heel, causing maximum tickling in both directions. The tail (or at least a tail) now brushed against the backs of her knees. She had no idea such a spot even was ticklish, but the feathery fin was the perfect tool for the job apparently. She couldn't believe she could feel every bit of individual tickling so clearly, but she could, and so the terrible sensation of the tail on her legs only added to her torment, just as the various techniques being used on her ribs, bellybutton, pits, and feet did.
And speaking of feet, before long yet another double pair of hands joined in at her feet, one pair holding her toes back, the other tickling below her toes full time, while the claws running up and down her feet now only tickled the balls, heels, and oh so sensitive arches. She had no idea how four mermaids were all managing to fit her hands in, but that wasn't really her problem. What was was the horrible tickling that resulted. They seemed to love her feet especially, perhaps because they had none, or maybe just because there were so many way to tickle them.
Out of the corner of her eye, she could she a mermaid's head poking above the water. Not good. There was only one reason she'd emerge from the water, and that was to get to the right position to apply her warm tongue to the helpless pit in front of her. The hand moved out of the way just she she reached her target, licking up and down the smooth flesh. She couldn't believe anything could tickle more then the claws, but there it was. It was like slimy sandpaper, and every lick sapped what little willpower remained. Even if she was wasn't pulled tight, she wouldn't have had the energy to struggle after a few ticklish licks. Next came a tongue on her other pit, the two of them alternating . One licked up her poor armpit, then the other, then the first, a constant cycle of ticklish torment, as another pair of hands appeared at her sides. Perhaps the one at her pits was responsible. Or perhaps she was the one that circled a tongue around her bellybutton as the tail moved away, before sliding it into the tiny, ticklish hole, extracting even more ticklish laughter. Or perhaps the one who had been using its tail there was responsible, assuming that wasn't the same one who had been tickling her ribs the whole time. She honestly knew nothing about the mermaids that tickled her. How many there were (though she could get a pretty good idea of the minimum), whether it was always the same one, or why they were doing it. And she didn't care. All she cared about was it ending. But it wouldn't. At least, not for long. She'd near unconsciousness, and they'd stop, letting her rest, then she'd awaken, maybe be given some food and water, maybe hang around for a while in anticipation of the next tickling, maybe get tickled some more right away, and the cycle would begin anew. Sometimes they'd start off slow, as the did today, other times they got right into it, tying her ankles and starting the torment everywhere at once. All that mattered to her now was that, far more suddenly then they started, they stopped. All sensations ended at once as the knots on her ankles slipped off. She soon drifted off to sleep.
She awoke to something strange: laughter. More importantly, not her laughter. Opening her eyes, she saw it was now night, the inlet lit by a full moon. That was nice. Though she could rarely see them anyway, when it was perfectly black, the tickling felt so much worse. And because of the light, she could see the source of the laughter: the mermaids apparently had a new captive, was was hanging from the same mast, facing her. She couldn't see any mermaids, but they were apparently hard at work, as the girl laughed and laughed in the moonlight, begging for mercy. She remembered when she had begged, when she though maybe it would make a difference. She wondered what the new captive would mean for her. Maybe when they had a new girl to torment, they let the old one go? The answer became all too apparent as she felt a fin dart across her stomach.