Thanks for the recs lol, but the reason I asked was because I was curious to know how such an ordeal would realistically affect the human body in detail. It’s fairly easy to assume death would be the outcome, but even so, how is it caused? Did the intestines rupture? if so, at what level? What damage was caused along the way? Would the pressure affect any other internal organs? in what way? And so on and so forth.
I am a bit late to the party, but I'll give my try. Not a medic myself, but I do have some basic knowledge of anatomy, so I guess that will help a bit.
First, lets look at some IRL reference points.
1. For tentacles it would be colonoscopy, of course. That bitch hurts - REALLY hurts. I know a person who did that without local or general anesthesia, and that person was screaming from pain - its that bad. Colonoscope is somewhat stiff, its movements aren't quite fluid, it will some moments poke at the soft walls of guts and will push against muscles that will try to push in the opposite direction. And contrary to what many believe, guts do have enough pain receptors to make this process so bad its often done under general anesthesia.
2. For cum inflation it would be enemas. Big enemas are usually not comfortable, but if water is pushed fast and in great volume, it will definitely hurt. I think, for the same reason colonoscopy does - it will go inward, muscles will try their best to reverse it, it will slow the flow, make some areas expand disproportionately, etc.
3. Your guts and stomach could be worn-down in some places by ulcers and other illnesses. Most people have at least some problems, and it will be a down factor for guts' durability. So, tentacles can poke and expanding cum will poke at wrong places and cause extra damage.
4. Gastrointestinal tract (GIT for short later) is really a one way pass. So, I would assume it will be somewhat easier to move things mouth-to-ass rather than ass-to-mouth. At least, muscles designed to move it one way will help guide whatever there is moving down compared to muscles trying to stop whatever going up.
5. Breathing can be blocked either by physical blockade, filling of lungs or pressure put on the ribcage. And I would assume, mass of tentacles pushing from below through the diaphragm could do the same. So, the throat must stay relatively clear, not much pressure put on the ribs and not too much tentacles and or cum filling the guts.
6. If there's shite, it will either be pushed by the invader or, which IMO is more likely, smeared alongside it. The former will cause either defecating or feces vomit, which could lead to rather nasty suffocation. The latter will apply extra pressure at the gut walls, most likely disproportional pressure after in some places shite will congregate, pushed by the invader. So, its extra stress.
With that done, lets move to some conclusions.
I am not sure all the way through by liquid is even possible, since the tentacles could guide itself and liquid will just expand everywhere, putting stress into every area it encompasses. My guess is that the guts will break way before liquid will expand ass to moth (or vice versa), given that you must put some pressure to move the liquid all the way through a few dozen feet of GIT. That's a pressure guts were never meant to handle, so I struggle to see how it could work in non-harmful way - maybe if liquid is poured VERY slowly, but I don't think it allows us to dismiss the pressure issue. Another point is that pose would probably play some role, allowing gravity to help the process or not. Also, cum is more viscous than water, meaning it will struggle to pass more, meaning, as far as I understand it, all of the above liquid-related problems, but worse.
Tentacles/small crawly creatures on the other hand? Yeah, why not. Thin enough, soft enough, precise enough - yes, it will work, probably hurt less than a colonoscope. Bigger ones? Killers. Also, lube must be top-notch to allow near-zero friction - and hey, if would probably be farmed for technical use, during which some pretty tomboy mechanic falls into the pen to get her guts tenta-drilled... I digressed.
And if there is not enough lube... Well, spare for the obvious rip and tear until its peritonitis... Did you know there is a condition where one section of the gut folds into the other, like when sleeves got all messed up, rolling into themselves? As nasty as it sounds - I don't want to even think about it. Now imagine tentacles putting so much friction against the gut they drag a section of the guts with them inside the other section. I know you probably had a tiny bit urge to puke - don't be ashamed to admit it, I definitely had one.
Another big I see here is locomotion. See, either the tentacles uses its own muscles and power of friction to slither up the gut (like a snake through a tube, pushing against the walls of the tube) or it will be pushed inside by the rest of the creature, much like some liquid would be. You see the problem here? The first option requires putting stress on the guts, the latter will require some level of precision even a robot will struggle with, probably - otherwise we will have a pressure enough to push a few dozen feet of meat (that won't me a small amount of pressure) applied on some unfortunate area of the guts.
But hey - we are not in the realm of IRL here. We are talking about hentai many-tentacled rapist from hell, so we can take some liberties, based on all of the abovementioned, to ensure the safety of GIT of whomever gets the tentacle D.
Spare for the lube point, which I've spelled already, first thing first, muscle relaxants and anesthetics. As you have seen, one of the core issues of the whole process is muscles pushing against the invader to basically deal extra self-damage. Another is the pain of some rogue jabs at the soft tender walls not designed to be jabbed. So, relaxants will help turn all those pesky unbridled muscles soft, allowing the tentacle to push against them without extra-resistance - how much damage would be done to lower stomach sphincter if its fully relaxed and provides little resistance? I image much less - and the numbing agents will do the rest of the job, meaning occasional jab or two won't become such a pain.
But here is a "but", big BUT, in fact. I have no idea what long-term effect complete GIT muscles relaxation could cause. Probably nothing very good, but I dunno - maybe they will just restart as normal after the effect wears off, or maybe they will all get crampy and messed up: GIT no work, human no live. Also, anesthetics works against pain, not damage - whatever some vidyagames would like you to think. Duh, an obvious point, yeah - but one worth pointing out.
Also, if you feel extra-assholish, switch anesthetic with something to raise sensitivity and/or aphrodisiac. Those mind breakes and ahegaos won't make themselves!
As for the breathing - if the throat's blocked and the fire's hot, the tentacle will see what's hot... Sorry, I have an OD of MGR:R music. So, the tentacles could provide the air - the most obvious path is to push an additional tentacle or two down trachea or even bronchi to pump air directly into the lung and pump away CO2. Or just pump the air inside and let it fart the CO2 out of mouth and nose alongside the main tentacle. The sky is the ceiling of your fantasy, err, so to speak. That is, if you don't want to go full tracheotomy route - but hey, it will work! But it will add "guro" tag, since it means actually fucking opening up of one's trachea from the front. With a sharp object, to bypass the throat in case of blockade. Yep, not the prettiest bit of IRL lore, I know. But I mean - we are pretty much discussing medicine anyway.
Secondly, we can go full magic/superscience/magical superscience. Make the lass/lad extra stretchy! Make her breath through skin! Make her extra-durable! Give tentacles sex-magic! The tentacles can lobotomize her through nose and ears (some-fucking-how... hentai artists and anatomy knowledge, am I right?) to experience everything as mind-breaking pleasure!
Aforementioned problems are from real anatomy, but in fiction you can apply non-real solutions to real problems. Once again - the sky is the limit of your imagination!
Me out. Hope it helped.
