There was a swimmer approaching Bigmouth cave. Her curvature was visible, if in parts rather tightly constrained, in a no-nonsense, sporty swimsuit. She had been diving in the area slightly further away before, without extra oxygen, seemingly just exploring the area near the surface.
On the maps, Bigmouth cave is shown as having an underwater entrance to a little hidden chamber, which awakens the curiosity of the young adventurous type. Like extreme underwater geocachers, they egg each other on to try to bring a little memento into the cave as a sign that they managed to get there, managed to beat the challenge.
The adventure could be quite exhilarating, even when cautiously contemplated beforehand; the chemicals of excitement released by these daredevils could be tasted hundreds of meters away.
This swimmer was letting off a lovely mix of stiff, almost aggressive determination, with clearly observable streaks of trepidation. Judging by her earlier movements, the cave was at the borders of her free diving capacity, even with the extra boost from flippers. It was a risky endeavour, and she was deliciously aware of it.
Her diving mask was connected to a little hands-free light source. It sent flitting rays of endearing futility into the dark depths below her whenever she glanced down.
If only she knew what was lurking beyond her land-mammal visual capabilities, she would stay well clear of the entire bay. But she did not, and there was no harm waiting for her to collect herself enough to brave an attempt. After all, given the amount of hubris she was excreting, she could not possibly give in to her nerves. She likely had pride at stake, or something else thoroughly perilous.
It was all a matter of time.
She did not attempt the dive immediately, as was usual. She was circling around the area for a while, then went up for a break, and came back, not one ounce wiser or more cautious. It was as if some kind of other predator was waiting above the surface to mentally push her back in. This was particularly fortuitous; maybe after she had made the dive, she would in turn push the predator in as dessert.
That is, if she survived the adventure.
When she finally steeled herself, she moved fast. Down she went, reached the wide and welcoming cave mouth, then a few metres of darkness in a much more constrained space, fumbling forward at times in a tunnel part so narrow that it was not even possible to turn around.
Her lungs must have been feeling definitely uncomfortable by the time she made it to the air pocket.
It was connected to the outside through some tiny cracks, which were not enough to provide light into the little cavern. It only allowed for some shoulder space, but had little crevices to hold onto the treasures of those bold enough to enter, and there were hand- and footholds enough to not have to paddle continuously while admiring the trove.
Inhaling victoriously, she produced a little miniature unicorn with her initials in it, and wedged it between the rocks so that it would not wash away. The cavern was now hers!
Any other implications of changes in ownership she was not aware of at that very moment, yet.
The first fleeting touch of her calf made her jolt, but she seemed to shrug it off with a shake of her head.
A slightly longer stroke climbing up her thigh prompted her to dip her head into the water to try to see what was there. But of course there was nothing to be seen at that point. Not even little fish would remain around when faced with such a splattering of light.
Her heart was thumping harder in her chest, but her breathing was still determinedly level, trained. She would not be able to dive out while in a panic, she needed to stay calm and cool-headed through the long way out.
There would be no diving out before it was time, that much was for sure. So maybe a little calculated increase in panic was in order.
When she felt a tentacle curve around her ankle and hold on to it, she squealed reflexively, a mammal warning sign to warn off others. There were no others to heed her warning in this case. She burst into a cloud of adrenaline and fear, primed to fight, which was futile given the circumstances, flight, which she would not be able to complete while unravelled, or freeze, which seemed the exact right thing to do.
She was breathing unsteadily, but given that the hold had not done anything else sudden or surprising, she dipped her face into the water again. She was allowed a good look of the solid length of patently non-human tentacle around her ankle, before a cloud of ink engulfed her field of vision.
She tried for a moment to force her eyes to see through the blackness, during which the tentacle squeezed her ankle a little harder, until it definitely hurt but wasn't breaking anything yet. She lifted her head back up to inhale in reflex, and the squeeze loosened immediately.
It was still there, she was still held by the ankle, but it was as if it reacted to what she was doing.
The swimmer was not stupid; after all, she did have the good sense to fear the dive beforehand. She tested - dipped her face in the water to try to look around, got squeezed hard again, lifted her head, grip loosened.
Now her heartbeat was increasing again, only it was mixing with delicious pack animal chemicals. Maybe she was contemplating gods and other all-powerful creatures, and being at the mercy of intellect rather than forces of nature, whether to submit or to try to apply more primitive strategies.
She was a natural freezing type, and while her contemplation progressed, so did two feelers climbing up her legs. She looked like she was evaluating negotiation strategies, or maybe just trying to understand what was happening through alternative means. In any case, as a result of this exercise bringing blood to her head, she turned off the little lamp and dipped her face into the water again.
The tentacle squeezed her ankle just a little bit, not painfully, just in acknowledgement. Two feelers that she would not be able to see in the trails of ink had reached her inner thighs, and when she tried to move her hands to touch them, the pressure on her ankle increased suddenly again. She hastily retreated, excreting another cloud of fear, submissiveness, and a hint of very, very guilty arousal.
When she dipped her face into the water again, it was as if she was trying to wash the heat from her cheeks. She was rewarded by one of the slimmer feeler tentacles slithering past the edge of the fabric in her swimsuit, and her entire body electrified. In response, a slightly more forceful pass pushed aside the theoretical protection and brushed against her labia.
Astutely, she determined now was a great time to panic a little bit.
The squirming brought in more tentacles to hold on to her second ankle and waist as well. To the swimmer's horror, the part wrapping around her waist was thicker than her wrist, and the trailing part went on to explore her breasts.
She squirmed futilely against the hold, but when she tried to apply her fingernails or grab the tentacles sneaking into her bodice, her captor would pull her downwards, threatening to submerge her fully. She desisted promptly. If she could possibly get away from her predicament without being drowned on top of everything, that would be a definite improvement.
/Focus on how nice it feels that you can still breathe. It almost helps you to not think about the thing that slithers into your vagina. It does not quite help enough to make you not make distressed sounds when you feel another tip press against your anus./
The swimmer tasted sweet, as they always do, and she was patently terrified. The sensitive orifices in her body were getting filled and the feeling of invasion increased by further alien sensations everywhere else on her exposed skin as well as that seemingly protected by the swimsuit.
As a tip invaded her rectum, she actually tried to relax against it and allow it in without it tearing her. Another tentacle was sliding into her mouth and she very submissively opened it as wide as she could. As a reward, her sphincter was spared and the slimmer tip explored her anus while slowly sinking deeper.
Emotionally and physically exhausted, the mammal prey did not struggle against her three-way penetration any more. Confused tears were building up in her eyes but blocked by the diving mask. When she occasionally sobbed slightly with an inhalation, it jostled her body in fascinating ways.
It was time to sample one more burst from her.
With the more solid tips pulsating and squirming in all orifices of the helpless swimmer, special feelers settled around her nipples and the length between her labia up to the clitoris.
Then the electric shocks started.
First mild, so that her mind barely registered that something strange was going on. She made a few futile movements against the restraining hold, but did not protest further than that.
Then they increased in intensity, spiking first up so that by her jerking response she definitely noticed the shock, and coming slightly down until settling just below the border of causing pain. On average, in any case.
She spasmed slightly every time when the synchronized shocks sent waves of intense sensations through her sensitive surfaces, but when they grew more steady, her reaction switched more towards a coiling up of a special kind of tension. She let out an accidental moan and her vaginal muscles squeezed around the tentacle squirming inside her.
It did not take much to push her over the edge. The mechanism was, in the end, quite straightforward, at the end of the day. She had nowhere to run, she had already given up on trying to think her way out of the situation, and she could feel the calculating power in the coils around her. She wanted to please, she wanted to be a good little prey, in the hopes of not being pulled under, so she was open to suggestion. And the messages she was getting were quite straightforwardly suggestive. She started to push her groin against the feeler, move against the invading tentacles, release a different cocktail of tastes from her pores. She made little mewling sounds around the cold, slick meat filling her mouth, and squeezed against the other parts inside her.
She'd even try to caress the tentacle in her mouth with her tongue, and apply some suction around it, experimentally, as if to understand if this was expected of her. She played along, all the while coiling up tighter and tighter.
When she orgasmed, her vagina released more fluids to slicken the invading object in it, her muscles spasmed all over, and her mouth made louder sounds to the level permitted by the meaty gag. Then she released the afterglow chemicals, and they were hungrily savoured.
Afterwards, the tentacles withdrew around her and she was left alone in the darkness. With shaking hands, the swimmer turned her mask light back on. After a quick dip of her head into the clearing water, she was sufficiently convinced that she was alone.
She then removed the mask for a second to wash the tears and snot from her face, as a first step to steel herself for the long dive out.
The salty treats were silently enjoyed as a dessert. One more rewarding stroke on her calf made her tense for a moment, then relax again.