Part (and Inside) Of Your Worldddddd!!

Winner of the Term 4b Fic Poll! The winning theme was 'Octopus Merman Bakugo fucks Deku'. This one actually went through two different versions before I settled on this one - which ended up being my fav version! 

WARNING! This is noncon -> dubcon -> consensual 

also, I hate titles. I just....I hate thinking up titles so much OTL T A T 

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He knew right away that this was all some stupid joke, perpetuated by the extra assholes who thought he was naïve enough to not catch on right away. Watching their dumb faces light up with delight at him having, supposedly, bought into this completely unbelievable lie made him want to bring it to an end right there but honestly, this dumb prank gave him an opportunity he’d been waiting months for. So, for the sake of finally fulfilling a desperate, gnawing want, he played along, snarling and growling as they expected him to, loudly declaring that he wasn’t a coward when they insinuated he was too scared to go through it. With that exclamation, they headed towards the human settlement that was plopped right in the middle of the ocean. All the way, they were smirking over their shoulders, nudging and giggling quietly amongst themselves, as though he wasn’t right behind them. Katsuki had to fight hard not to roll his eyes. These dumbfucks really had algae for brains. Almost made him wonder if they’d been able to convince anyone else that this idiotic prank was actually true. If so, whoever had genuinely fell for it deserved to be sliced up and served to the humans. 

Once they were close enough to the human settlement, Katsuki took the lead, swimming ahead, his tentacles sending him gliding through the water. He headed straight for the docks on the right side, where just the human he was looking for was sitting on the lowest dock, his legs in the water. From behind him came the jeering cry of idiots. Seemed like even morons like them could pick up on him having found someone. They snidely pushed him to do it, betting amongst themselves that he’d chicken out. Katsuki ignored them. A wide grin spread across his face. He dashed forward, stopping just next to the human’s legs. He paused for a moment, wondering what was the best way to go about this. It’d be easiest in the water but…uh, human. Couldn’t exactly hold his breath for that long. He wanted this adorable fucker to be alive for hundreds more rounds of this. That left only one option: up on the dock, it was! 

He popped up out of the water by the human’s legs. Bright green eyes widened in shock. The freckled, fluffy haired human jumped backwards with a yelp. Grabbing hold of the edge of the dock, Katsuki yanked himself out of the water. His tentacles wrapped around the wooden posts, giving him more leverage. Mouth hanging open, the human toppled down onto his butt, gawking up at him in a way that really made Katsuki just want to mess him up. Katsuki dragged his tongue over his bottom lip, grinning down at the adorable human he had had his eyes on for months now. There was a chance another human could stumble upon them but over the many times he had watched this particular human from the water, not a single other soul had been seen. He was fairly confident on their first time would be a private affair. 

“You’re a-“ The human gasped, reaching out to him with a trembling hand. 

While this situation was allowing for something he’d been desperately wanting, it also meant that he didn’t have a lot of time. Ah well, this would be far from the last time. Swinging his tentacles forward, he wrapped one around the human’s legs, dragging him in close. He yelped in alarm, surprisingly sturdy hands flying down to Katsuki’s tentacle. Blunt nails dragged across the smooth, wet surface, finding no purchase that’d allow him to get free from Katsuki’s hold. Not wanting him to struggle too much, Katsuki wrapped another one of his tentacles around the human’s wrists. Staring up at him with wide, terrified eyes, the human started to cry out something but Katsuki lunged down, curling his large hands around the sides of his face, and smashed his lips against the human’s in a rough, possessive kiss. The human tensed up underneath him. He heard him suck in a sharp breath but he didn’t exhale. A wild trill of heat roared through him. These lips…he had imagined kissing them so many times, he practically knew them already but this…fuck, gods-! The human’s pink, plush lips were so soft! So sweet! 

Moaning low in his throat, Katsuki sucked his bottom lip between his teeth, nibbling lightly on it. The pressure of his teeth moving across the sensitive underside of his lip must’ve jerked the human out of his stupor. He began to struggle with renewed fervor underneath him, twisting and bucking in an attempt to get Katsuki off. Katsuki curled his tentacles tighter around him in response. He could’ve kissed him all night long but he was already pushing his luck with being out in the open – time to get to what he really wanted. Pulling away with a sharp breath, Katsuki straightened up, grinning broadly. The human’s face was flushed a bright, beautiful red. His mouth hung open, giving Katsuki a tantalizing peek at his pink tongue. Just underneath where his tentacled tail ended and his torso began was a familiar pulse of tingling heat. Katsuki’s smile grew even further. Just kissing this adorable fucker had already gotten him that far? Well, not that surprising, all things considered. 

“What’re you-“ The human began to gasp. 

Since they were out in the open like this, and he was already this turned on, it didn’t really make sense to draw this out. All the good foreplay stuff could come later. Right now…he just wanted to be inside his adorable human already! Grabbing the hem of his trousers, Katsuki yanked them down. To his delight, despite the human’s struggling and protests, he was already rock hard. His adorably plump cock bounced free of his pants, proudly standing straight up, as though to admonish Katsuki for taking so long to get it out of there in the first place. Pearly drips of precum swelled to the dribbling, down the length in a tempting line of creamy white. Swallowing hard, swamped by a dizzying heat, Katsuki didn’t bother trying to stop himself. Bending down, he swirled his tongue around the head a couple times before taking it into his mouth, sucking lightly on the spongy mass. The human let out a sharp, jagged cry, flushing an even darker shade of red. A deliciously salty bitterness spread across his tongue, quickly coating every surface in his mouth. 

Moaning, Katsuki pushed down further, taking in every last inch of the human’s plump cock. So small-! So cute-! His cock twitched eagerly against his tongue. Precum leaked out at a constant rate. The human weakly tugged on the tentacles restraining him. Panting, whimpering breaths tumbled out from his gasping mouth. Tears welled up in those big, gorgeous green eyes. Katsuki kept his gaze trained on the human’s face as he sucked on him. Still resisting, huh? Well, not like he could blame him. Fine, he would just have to ramp things up. He was making a good expression but Katsuki wanted to be the cause behind an even better one. Slipping off his now saliva drenched dick, Katsuki curled one tentacle around each of the human’s legs, easily pulling them open, despite the human obviously trying to keep them clamped closed. He tore his pants off all the way, finally fully exposing his bottom half. He pushed the human’s legs up and over until they were hanging open his hand. Taking a plump globe in each hand, he spread him open, exposing his cute, pink hole. 

“Wai-! Wait-! Stop-! Don’t-!” The human cried out, shaking his head frantically.   

Drool poured into his mouth. A rush of vibrant heat spilled straight down to his base. With a shudder and groan, his slit burst open, allowing his cock to push out. Panting heavily, a dazed smile spread across his flushed face, Katsuki leaned down to press his tongue to the human’s hole. A hard shiver shook his smaller body. The human let out a strained wail, his hips bucking. Curling an arm around his midsection to keep him in place, Katsuki dragged his tongue across the puckered entrance, coating the sensitive skin in a heavy layer of saliva. Gods…sweet…he was so sweet-! So cute-! Why had he waited this long to taste him?! Why did he wait until he had some arbitrary reason to finally make this incredible human his?! Ah, he should’ve done as soon as he laid eyes on this adorable, beautiful human. He was his…he was always meant to be his! Gazing down into the human’s cute, flushed face, Katsuki snaked one hand down to slip it underneath the human’s shirt. He pushed it up around his shoulders, revealing his belly and chest. Katsuki smoothed his hand across the human’s hot, sweaty skin, adoring the way the muscles twitched underneath his touch. 

“Stop-!” The human gasped, his cute voice now laced with an undeniable heat. Katsuki’s lips curled into a smile. “Please stop-!”

“You don’t sound convincing at all.” Katsuki teased. He curled his other hand around the human’s stiff penis, his grin growing when a gentle pump pulled a breathy, whining moan out of him, “You’re not being honest at all. Here,” Katsuki gave the human’s cock another pump, “and here,” he sucked hard on his hole, “are saying what your mouth refuses to: that you want more.”

“No-!” The human whimpered, shaking his head. “I-! I-!”

This playing tough act was getting a little old. He didn’t mind a little resistance at first – made the human finally submitting him all the sweeter – but it was getting to be about time that the words he wanted to hear came tumbling out of the human’s adorable mouth. Good thing he knew just the way to make him be honest. He brought one of his tentacles to the human’s mouth, taking advantage of him rapidly panting and gasping to push the tip between his plush, pink lips. The human’s eyes widened. His tongue wriggled underneath his tentacle, creating a sensation that was incredible. Moaning, a shiver racing through his body, Katsuki began to pump his tentacle in and out of the human’s mouth. Ah…fuck…it felt so good…! The human’s mouth was so warm and wet – it fit perfectly around his tentacle. When he pushed in deeper, the human tensed up, his cock twitching against his palm. Did he like it a little rough? If that was the case…Katsuki dragged a tentacle across the human’s chest, crushing his nipples, fondling and squeezing his pecs. He pushed the tip of his tentacle past the back of the human’s mouth to shove down into his throat. The sight of his throat bulging out from the sheer size of his tentacle nearly drove him to his breaking point. 

A powerful shudder shook the human’s body. He squealed loudly, the sound muffled by his tentacle. Precum dribbled out of his twitching, pulsing cock, creating a long stream of clear fluid down his stomach. Satisfied by how thoroughly drenched the human’s hole was, Katsuki slipped his tongue inside for a quick taste. Unsurprisingly, a wave of sweetness coated his tastebuds. The human moaned even louder, his hips straining forward. Ah, this was bad-! If he didn’t move this along, he really was going to lost control! Slipping his tongue out, he replaced it with his fingers, slipping in one at first but when he met no resistance, he pushed in a second then a third, rapidly pumping the digits in and out to coax the human’s hole to soften and stretch. Writing underneath him, eyes clenched tightly shut, drool streaming down his bulging throat, the human wailed and moaned. His cock was a sloppy mess in his hand. His nipples were hard and swollen underneath the constant assault of his tentacle. Inside, he was so warm and wet and soft. It took practically no time at all to get him ready, though he was ready to burst by that point. 

Pulling his fingers out of the human’s drenched, sloppy hole, Katsuki straightened up. He slipped his saliva drenched tentacle out of the human’s mouth. As good as it felt to rub that tight throat, he didn’t want to miss a single sound that he made. Dazed, heat hazy eyes swung up to look at him. Katsuki smiled widely, his cock twitching excitedly. Gods…fuck! He was so cute! Curling a hand around the base of his fleshly cock, he brought the large, angled head to the human’s hole. His green eyes widened, though the panic and alarm that had marred that gorgeous gaze earlier was nowhere to be found. Not quite as excited as he wanted but that was soon to change. Leaning forward, he pressed the tip to the human’s entrance. He curled his tentacles tighter around him, anchoring them together as he slammed forward, driving the entirety of his cock deep inside. The human wailed loudly, throwing his head back. His tongue hung lewdly out of his gasping mouth. His insides clamped down around Katsuki’s cock, squeezing him so strongly, it came close to hurting. Choking out a strained groan, irritated by how close he came to cumming from just entering him, Katsuki took a short moment to compose himself before he started moving. Since the human obviously enjoyed this being rough, he set a hard, fast pace from the first thrust, repeatedly ramming into him, sending him jolting forward with every brutal slam of their bodies. 

Fuck-! Fuck-! It felt so fucking good-! He was so hot, so wet inside-! His cock…his cock was melting! He was being milked by the human’s hole-! His mind went completely blank. All he could think about was how cute he was, how good it felt to be inside him, how he wanted even more. Struggling to keep his gaze trained on the human’s adorable face as pleasure surged through his body, Katsuki stroked his cock off in time with his thrusts. Just as he thought…every sound that came from this stupidly cute human was incredible. All of his resistance was gone. Mouth hanging open, eyes rolled back into his head, flushed the most gorgeous shade of red Katsuki had ever seen, the human was already a mess – squealing, wailing and moaning as he clumsily rolled and wiggled his hips. A wide, lazy smile spread across Katsuki’s face. He momentarily stopped thrusting to wrap his arms around the human’s trembling form. 

Reclining back, using his tentacles to create a cushion to keep himself upright, he pulled the human up so he was sitting in his makeshift lap. In this position, the human was pushed even further down his cock. Crying out throatily, his eyes stretching wide, the human bucked his hips a couple of times, precum spraying onto Katsuki’s stomach. Squeezing him close to his chest, Kacchan dipped down to capture that messy mouth in an equally sloppy kiss, shoving his tongue between the human’s plush lips to get another taste. Moaning loudly, the human clumsily returned the kiss – hesitant and slow at first but quickly becoming more confident when Katsuki moaned appreciatively. He released the human’s hands, though kept his tentacle poised to grab him again if it looked as though he might try to push away. Not that he was expecting such a thing to happen, given the human’s current state. Unsurprisingly, the human looped his arms around Katsuki’s shoulders, anchoring them closer together. Gods…he really was going to get addicted to this. The human’s heat…his scent and touch and taste…he couldn’t get enough…he wanted even more! 

“Does it feel good?” Katsuki cooed, nuzzling his cheek, dragging his blunt nails down the human’s sweaty back.

“Good-! Good-!” The human cried, “Feels so good-!”

“Hey, tell me your name.” Katsuki leaned back just enough so he could look at the human’s face, brushing his fingers through his sweat soaked hair. 

“I…Izuku-!” The human whimpered, his hips bucking hard, grinding his cock against Katsuki’s belly. 

“Izuku…” Katsuki breathed, a smile spreading across his flushed face. Ah fuck…even saying his name felt amazing. Dipping down, he captured Izuku’s mouth in a hungry kiss. A cute name for the cutest fucking human he had ever come across. Peppering little kisses all over Izuku’s flushed face, he murmured, “Katsuki.”

“H-Huh?”

“My name.” Katsuki said with a smirk, “You wanted to know, didn’t you?”

Exhaling harshly, his dazed eyes focusing on Katsuki’s face, Izuku audibly gulped, “Ka…Katsuki?”

......oh fuck. He was done for. He was completely and utterly done for. He had already made up his mind that this adorable human would be his but…a broad grin spread across his face. It was probably more accurate to say that with that one husky utterance of his name, he was his – fucking spellbound, trapped in his metaphorical net, and a bunch of other nauseating stuff that conveyed the simple fact: this human now held his heart, and he was about to let him let it go. Grabbing a handful of Izuku’s hair, Katsuki yanked him in for another kiss, dropping his other arm to wrap it firmly around his midsection, squishing them even closer together. He ramped up the pace of his thrusts, rapidly pounding up into his hot, tight hole. Izuku moaned and wailed into his mouth, clinging desperately to him. Good…fuck, fuck, this…this…it felt even better than before! The pleasure was even more intense, pushed higher and higher by Izuku reciprocating! Cumming…fuck, fuck-! He was gonna cum! He was-! 

“Kat-!” Izuku pulled away from the kiss to gasp out. 

Dropping his face into the curve of Katsuki’s shoulder, his hips rapidly bucking in time with his thrusts, Izuku let out the most gorgeous moan he’d ever heard. His small body violently shuddered in his hold. His legs curled tighter around him. Blunt fingernails dug into his skin. His cock twitched hard against his stomach as thick ropes of cum sprayed out of the slit, splattering all over his skin. His hole clamped down even tighter around Katsuki’s, squeezing and milking his cock. With that intense pressure, and the fact that he had made Izuku cum, Katsuki stood no chance against the rampaging ecstasy that came racing out from the pit of his belly. Snarling low in his throat, he lunged forward, sinking his sharp teeth into the soft flesh of Izuku’s shoulder. His skin burst underneath the points of his teeth. As Izuku’s blood laced across his tongue, Katsuki thrust up hard one more time, shuddered and moaned, his penis swelling up even bigger, stretching Izuku further. A torrent of sticky, burning hot cum flooded out of his cock, thoroughly coating Izuku’s insides. 

Breathing heavily, his tentacles constricting around Izuku, it took Katsuki a few moments to recover from the immense pleasure of his orgasm. When he was finally able to relax, he was dismayed to find that he had bitten Izuku a lot harder than he should’ve. What second round they might’ve had was now out of the question – merman bites, especially ones as bad as this, were serious business. Izuku needed to get to a medic quickly to get this thing looked at. Sighing in frustration at his own stupidly, Katsuki dragged his tongue along the bite, murmuring, “Sorry, I didn’t mean to-“

“It’s okay…” Izuku breathed, a dazed expression on his adorable face. Swallowing hard, he shakily slumped forward onto Katsuki, who was momentarily nervous that he was going to pass out but, to his relief, Izuku tightened his hold around him, keeping them close together, “Can…can we do it-?”

“Nope.” Katsuki interrupted him, lightly patting the back of his head, “Go get your shoulder looked at first then come back.” He leaned back to flash a sly smile down at the brightly flushed Izuku, “I’ll be waiting for you.”

To his delight, Izuku stuck his bottom lip out in a pout but one look down at his shoulder was more than enough to convince him it wasn’t a good idea to leave the wound unattended. Frowning, Izuku untangled himself from the hold of Katsuki’s arms and tentacles, wriggling backwards across the dock. He stood, tugging his pants back into place but left his shirt opened so as not to get even more blood on his shirt. Before he turned to leave, he paused, glancing down at Katsuki, “You…You’ll be here when I get back, right?”

Katsuki’s smirk grew even bigger. Reclining back, his tentacles lazily stroking Izuku’s legs, “Yeah, I’m not going anywhere.” He looked down at his still rock hard, visible cock, which twitched excitedly when Izuku followed his gaze and flushed brightly once more, “Not even close to being done with you so hurry up and get that patched up. Don’t keep me waiting too long.”

Izuku gazed at him silently for a moment before offering a smile of his own, “You’ll be here waiting no matter how long I take.”

It wasn’t question but a simple statement. Katsuki snorted, giving Izuku a little push with his tentacle. He wouldn’t admit to that being right, despite it being absolutely right…well, to a certain point. If Izuku did end up taking too long, he knew of ways to getting into the settlement so he could track him down. He kept that little fact to himself, though, as Izuku turned and jogged up the dock. Katsuki waited until he was out of view then jumped back into the water. Those annoyed extras were long gone – probably in a panic that he had ‘fallen for their trick’. Dumbasses – who would honestly believe that a merman rite of passage was fucking a human, and that he wouldn’t be a merman until he did so? Considering how much the Elders emphasized to be careful around humans, only a complete moron would think that was actually the case. Those idiots were probably convinced he was the dumb one but really, he did have to thank them…at least, in spirit. If it wasn’t for this stupid prank, he might’ve never finally gotten that fucking adorable human.