Ok I had to repost this to make sure I get someone's name in here properly.
Sorry it took some weeks to finish, school and holidays are tricky, but both stories are done.
Special thanks to  MrRainbow for letting me use his pictures for both stories. Not only as thumbnails but also as sparks to this story.

SUBMIT
Arminus walks from the Asylum Courtyard Bonfire to the double doors. “Before anything, I need to retrieve my souls before I lose them,” he says to himself. He triple checks his gear: estus flasks, miracles, armor, rings, and weapons. “That thing will drop above like always. I died somewhere in the middle, so I retrieve my souls and kill that dumb demon. Its hammer isn’t a problem thankfully, but those fat feet quake the ground stomping anything underneath.” He pauses briefly remembering those toes over him. “(shuttering)… Its belly is big and barbarous and can launch me with a hip check, depending if it doesn’t (gulps) “flop” on me. And I can’t attack from behind because now it knows how to use ihhh…. Iihht…. Iiihhtss….” He couldn’t control the stutter when speaking that single word. “Buuhh Butt,” the sleeper agent muscles in Arminus trembles terribly in terror when hearing that trigger word. Frozen for a few seconds, Arminus headbutts the door to break from his mental prison. “Ooouuch, ok ok ok (breathes) I can do this. With a personal pep talk he opens the doors and walks in.

Creeks from the door battle cry in the large, rugged hall, alerting the Asylum Demon to fight. Arminus looks up after opening the doors to see something huge in the middle of the same hall. The 40 ft smelly pear-shape, bottom heavy demon rests his hands on his hammer with the bell end on the ground. Arminus stands impromptu the demon’s figure. “What the hell is going on, you’re supposed to leap down not stand there.” While comprehending, the doors shut behind him, no going back now. He braces himself stable and investigates the room for his souls. “It was in the middle I know it or is it behind the demon’s tall, terrific tallness….…. Did I just think that?” The Asylum Demon curves its snarling face into a smile and lifts its hammer bell up to reveal the green illuminating light of Arminus’s souls. “What’s your plan here?” Do you even know what that is? Your jump entrance was probably the only intimidating thing you had.” Upset from the demon’s concealment, Arminus accuses it aloud, but with a worry in his tone. Earning him a low titter from the Asylum Demon.

It takes one step forward flopping its frame standing even closer to Arminus’s souls and resting its hammer bell down on the ground in its right hand. It points at Arminus first then points to his weapons. Arminus follows its finger to his talisman and mace and looks back to the demon. With a devious smile, it points down to the floor indicating to Arminus to drop his weapons. “Give me a reason why I should, you putrid pack of pudge?” Arminus retorts. Unshaken by the insult, the demon steps backwards to raise two fingers. 1: it opens its palm towards Arminus’s souls on the floor. Arminus controls himself a little realizing the demon is offering his souls back. “But what’s catch in option two?” he asks.

2: the demon turns around, each step shaking its body mass in ripples, to show its backside. Making the demon’s already putrid smell worse. “Uuggghhhhnnn” Arminus covers his nose to prevent the smell. The demon veers its head over its left shoulder grinning and slaps its hip with its left hand. Creating larger ripples that shakes the demon’s huge hindquarters. Arminus’s brows raise viewing the spectacle of ass action in front of him. “That is…. astonishing….. uugghh I mean appalling,” he internally fights with himself closing his eyes and shaking his head to get a grip, but the Asylum Demon notices Arminus’s struggle over its body and this expands the demon’s interests.

The demon rotates its body forwards and stares down at Arminus with a stern face and points its fingers down again for him to drop his weapons. Arminus stands clueless of what to do. Thoughts race in his head. Arminus craves to see the Asylum Demon improve by any means necessary, even if that means being subject to this demon’s, desires. However, he is also livid at the demon. After giving the demon 30 humanities on his own accord, the demon kills Arminus in a jeering distasteful butt crushing defeat. Arminus only wore rags with no weapons and no rings, making the fight, literally, heavy in the demon’s favor. Arminus closes his eyes, what choice should he do?

SUBMIT to the Asylum Demon so he can gain his souls but become vulnerable.
Or
FIGHT the Asylum Demon to gain his souls and show this thing who’s boss.

(Inhales) (exhales) “I am here for my souls, but most importantly, to upgrade this boss.” He quietly reminds himself. He drops his weapons in his inventory and is left with empty hands. The Asylum Demon presents a pleasant posture at Arminus’s choice. It too, tosses it weapon against a far wall. It then turns its body to the right facing Arminus. It gently gestures from its left open hand pointing towards his souls to grab them. Arminus walks forward eyeing the souls and ignoring the demon, “Huh, that was easier than I thought.”

He walks towards the souls nonchalantly a foot in front of the demon. It churns a smile as he gets closer, and as he passes the demon halfway, it swivels its right leg and lifts its left leg showing its three toed under foot. Arminus hears sandpaper rubbing behind him but couldn’t react quickly enough to dodge the heavy foot slamming into his back and onto the ground. Arminus raises his head to see his souls 6 feet out of grasp. The little human ant struggles underneath to escape its captor and reach his souls. “Hey, step off, let me grab my souls.” He demands, but with no attainment. Because all the attainment went to the Asylum Demon holding its prey beneath its paw. It did not use a lot of pressure because it has plans for Arminus later. It simply smiles and shakes its head no. “I can’t move, it’s gonna crush me…. Wait where’s the crushing and why am I lull right now.” While questioning his thought, the Asylum Demon gently rubs the balls of its feet over Arminus’s legs. He attempts to escape, but halts as the foot mildly restrains his torso. The demon caresses his back side-to-side in an arch motion to prevent any injuries. “Can you plea…ooohh stop trampl-aahhhhh.” The easing massage restricts Arminus from speaking a full sentence. The demon moves its foot to the shoulders, some cracks of not bone, but cartilage emit from Arminus’s body. “Little higher, higher, hig- uuuuhhhhhh yeeeaaa.” His gentle voice transmits to the demon he is happy, until (sniff) (sniff).

“Awwwggg my Go-(cough) that’s just horrible?” Arminus yaks a bit which startles the demon to lift its foot. The feet, though good at massaging, had a raunchy smell to them. The demon looks down with concern to check on Arminus who is sitting on his back coughing. He looks up at the demon to say, “I’m sorry, the smell caught me off guard. Actually?” He grabs 5 green blossoms from his inventory, shreds them a bit, and plugs his nostrils. The gentle giant looks down with a query remark on his face. “Here try it now.” The demon does as he asks and hovers its right foot above Arminus laying on his back. When looking at it, the foot almost covers Arminus from head to knees, and wide enough to cover his shoulders too. The demon’s foot descends and compresses his mid torso, but with enough breathing space. “Good, the green blossoms work, ugh (crackle) ahh,” the sound of falling acorns ring from his back as the demon alters between its weight pressing which tenses Arminus and releasing which relieves Arminus. Uugghh (crackle) aahhh, ooohhnngg (Crackle) oouhhhh, nnggghhhtt (CRACKLE) uuuaaaaaggghh.

This routine keeps going for 5 minutes until the demon shifts nearly its entire weight into one final (CRACKLE!!!) Purging his body from stiffness, Arminus moans in bliss. “I didn’t realize I was that rigid; I almost don’t want to move.” Removing its foot, the Asylum Demon leans forward observing its happy relaxing subject. A cheerful chortle leaves its mouth as it carries its him with both hands. Its hands are crummy, but the care behind them makes up for it. Arminus and the demon observe each other at the demon’s head level. Looking at its belly then back at him, it smiles and hugs Arminus face first against its bolstering belly. The feeling of a wavy waterbed smears over Arminus as the demon puts some heftiness towards its hug. He turns his face to the side to breathe. Thankfully the blossoms divert the smell, alas that didn’t help him get enough air in. He begins to slap the demon to get its attention and hopefully some air. Thankfully the demon lifts its arms to stop hugging, “(deep inhale) Thanks, I almost… (shifts body)… What the… (shifts harder)... I can’t move.” The adhesive sweat from the demon’s skin is securing Arminus to its stomach. Bellowing laughter comes from the demon as it sees this little human fly sticking to its tremoring torso trap. The Asylum Demon decides to go on a little stroll, with heftier steps. The demon’s giant gut gyrates up-and-down with Arminus along for the ride. Sadly, that didn’t shake him off, if anything this made him blithely bashful. “This is fun and all, but could you get me off now?” he pleads. The Asylum Demon leans its head down over Arminus who stares back up to its sunny smirking face shaking no. “I didn’t think you were gonna help me, not now at least,” he says to himself.

The demon walks around the hall with Arminus sticking to its gargantuan gut. It gurgles and joggles Arminus franticly with every step it takes. This makes him dizzy, but also somewhat giddy too since he has been breathing in the stimulant green blossom nonstop. This plant helps heighten stamina, but too much of it can render someone’s demeanor to two extremes, lazy or crazy. In Arminus’s case, he turns into a comatose child. The Asylum Demon glares down again at its dopy detainee who in returns gleams up, “he he he heeeyyy biiiggg ggguuyy. Hooowwss iiitt goooiinnn?” Arminus asks in a giggling tone. This entices the demon with a feeling of control, it knew the human is secretly submissive, but didn’t expect him to be this frivolous. The Asylum Demon purposely takes stouter steps as it roams the hall STOMP STOMP STOMP STOMP STOMP. These stomps greatly tremor its tummy tossing Arminus tigerishly. Each one moves its stomach up, down, left, right, diagonals, and circles giving him a roller coaster ride.

Pleasure is seen from both the captor and captee, with nothing to stopping their fun, except. FWHHIIP. The demon’s tummy tosses Arminus into the air, who didn’t render his situation yet, and launches him 20ft into the air straight above the 40 ft demon. It spots the human and comically cackles at the sight of him but plans to catch its human. But how? Its arms aren’t long enough to catch him. Arminus floats in the air with the blossoms still in his nose, “Wwweeeee I caaaannn flllyyyyy.” This clueless clod starts falling, at a height that will surely kill him. Thankfully, PWWOOOMMGGGG he bounces up, PWWOOMMGGG, and again, PWOOMGG and again until finally a PWOMP. Arminus lands face first into the Asylum Demon’s potbelly pudge, which saves him from falling to death. The demon laid down beforehand to make sure it covers most of the area to save its silly stooge. Arminus pulls his face off its flab and stares over its belly at a green glimmer between the demon’s legs. “Heeeyy iiissss thaaat myyy… myy… my souls!” he answers himself with more composure, his entire reason to come in is glowing right in front of him and he did not want to miss his chance. He scuttles across the demon’s belly stupidly, which grabs the demon’s attention. It feels him crawl up to its potbelly’s peak and kept going past it. Arminus’s haste causes him to lose his grip and fall off the demon landing, yet again, face first onto the floor.

The demon did not feel him on his belly but did hear a TWHUMP and a “Ouch” afterwards. A sinical smiles grows on its face, fully knowing what to do next. Arminus, unaware, reaches his arm out and successfully grabs his souls. “Yes YES YEESS, I got them back I- “he pauses his victory after viewing two lumbering legs on each side of him, and hears a stone rolling behind him. “no No NO NNOOOO-” SCRUNCH. The demon sits up and encases Arminus under is belly. Superficial satisfaction swells inside the Asylum Demon and begins to bounce and bash Arminus with playful intent. The ground is the immovable object, while the demon is the unstoppable force, and anything in the middle is, well, unable to escape the conflicting powers and poor (or prosperous) Arminus is the middle. The demon’s pleasant pounding prevents Arminus from moving for a solid 8 minutes. “I can’t move at all, and I am going to lose my souls again if I don’t get out.” Fear and excitement fill his mind during the demon’s enthusiastic onslaught. “Is there a way out of this? Is this all its weight? Should I stay still and endure it? Why is it warm under here?” The demon stops moving and leans back, giving Arminus a moment to breathe, not to escape “Man, glad that’s over.” He begins to move his arms and legs a bit, and notices something odd. “It’s surprisingly subtle under here and with little to no smell, oh yeah the blossoms.” He is unable to reach them in his inventory with the demon on top of him. “Hey, get off me please.” The demon felt its captor yell under it and responds back with a goofy grin and lifts its stomach to give him some seconds of air. Arminus replies, “Whew thanks I needed th-” WWHHOPP it drops its bulging belly. It laughs loudly and continues to plop its playdough pudge PLOP (lifts) PLWOP (lifts) PLWOMP (lifts higher) PLWOMMPP (lifts higher) PLWWOMMPPSS. Arminus braces with the demon’s motion. “Of course it does this, well at least it feels good….. wait why does this feel good?”

He ponders this question as the demon ceases his slamming. “It’s not hurting me, but…. playing?” He begins to recap his encounter with the demon and no matter how he deviates the reasons, the demon did not physically hurt him at all. “I need to get its attention.” He grabs the demon’s under belly and gropes it, earning him a groaning sound from his detainer above him. Who in return subtly shifts its stomach above him. After some minutes of pleasure, on both sides ;), the demon stands up and takes a step back to look down at Arminus. He doesn’t move for a minute due to his captors memorizing massage. The Asylum Demon peers over and sighs sensitively to its sweet subject. This breaks his trance and begins to stand and speak, “You didn’t mean to harm me at all from the very beginning, did you?” The demon shakes its head. Arminus kept going, “You gave me a back massage, a hug, carried me, gave me a belly ride, and used yourself as a trampoline to save me. Even while under your body, you didn’t intend to hurt me in any way.” Arminus looks at his health bar and notices it is halfway gone. “Ok well mostly hurt me in any way.” He takes a quick sip of estus and continues, “but… this is really weird… you haven’t hurt me at all… I guess I wanted to say….. mmmhhhh thanks.” He is terrible at giving grace and/or apologies, but the demon knows he is sincere. It nods its head at him, confirming that it accepts his thanks. A strange sensation of joy and relief hits him from its response. But he didn’t know why?

But the Asylum Demon then shook its head and raises 2 fingers. “Wait, am I missing something?” The demon reverts to 1 finger and gestures to the souls on the ground Arminus retrieved. “I know I grabbed them already.” Then it raises 2 fingers and turns around again with its head over its shoulder to show its pridefully powering posterior. Rosy cheeks blush on his face, “Oh yeah, I sort of forgot about…. That.” The standing demon flaunts its fat fanny closer to Arminus. Even while standing, it’s lumpy load of lard looms over him. But he isn’t tremoring in terror, he is anxious in anticipation. “Wait, before anything,” He grabs another 5 green blossoms, shreds them again and stuff them in his nostrils and lays down face up, “Ok, now I’m ready, just… please be gentle.” An abundance of absolute amusement surges into the Asylum Demon, what this human did shows his trust toward it. And it is more than happy to comply. Hovering its heavy hindquarter over its humble human, it heaves its hefty haunches on him entrapping his entire body yet again. The demon’s left lump fully covers Arminus, and it can feel him embrace it. The demon warmheartedly wiggles its left wad side-to-side on to top of him, fulling knowing he is enjoying the wingding weight. After 5 minutes, it rolls him over to its right rump and reestablishes its rubbing routine.

Arminus does not move while the demon has its fun with him, and ironically him with the demon. He then has an epiphany from his previous question, “I get it, I know why I feel relieved with the Asylum Demon.” It wards off its wiggling wagon and curiously carps to its friend, who in response tickles its tush. This makes the demon laugh and continue it prudent posterior press. “In the beginning this boss was a big bloke compared to the other ones I faced. But now it has evolved into something more than just a better fighter,” he smiles as the blossoms delude his mind yet again to be a dopy doll for his dominating detainer. “But a better being that knows it is powerful and can crush anything it chooses, unless it receives the same trust it gives to others.” After 12 minutes of wistful wiggles, the demon places him in under the middle of its ass and glares over its right shoulder grinning in glee. “And it’s been trusting me from the very beginning and hasn’t injured me once.” The demon cleaves its cheeks and slowly cuddles him closer to its colossal crevice. “So, I will show it my trust, by submitting to it completely.”

And with his final thought, the Asylum Demon clenches its cheeks in carnality around its captive. An hour combination of BWOMNG BWOMNG BWOMNG BWOMNG butt bouncing, GRAFFTT GRUFFTT GRAFFTT GRUFFTT glute grinding, and SQUENCH SQUENCH SQUENCH SQUENCH seat squeezing drew a blank in Arminus’s memory, but thankfully it is a good blackout. His new beneficial friend is really railing its rotund rear into him, maybe a little bit too much. The demon groans gleefully as it grinds the giddy goon like glue between its gargantuan grim glutes. GRIFF GRRUFF GRRIIFFFF GRRUUUFFFF GGGRRRIIIIFFF GGGRRUUUUFFFFFFF GGGGGRRRRIIIIIFFFFFF-SQUENCH. The demon halts as it hears and feels something wrong. It stops quickly, stands up and divides its derriere only to see ashes of Arminus fall out and a green puddle of souls replace his ashes on the ground. The demon’s heart sinks and hears the front doors open again. It turns around and sees him walking towards him. The demon kneels and bows its head down showing its apologies, but only hear his steps walking pass it grab his souls and SLAP. This brings the demon kneeling straight up and rotates its head to see Arminus’s handprint shaking its right ass cheek. “I got my souls, let’s get ready for round three. I believe there is some more ‘upgrading’ we can do,” he states in a more seductive tone. This reassures the demon that he is trusting and loyal to it and that pleases the demon with a wide grin. “Well…” he asks as he jumps into the fanny’s fissure facing out “…what are you waiting for?” The demon didn’t answer, it just smiles falls back and flattens its friend, again.

These two continue to ‘train’ with one another to improve each other’s move sets, but after a while it became more or a kinky club. And there are times where Arminus would homeward bone to the campfire to regain his health and magic, but sometimes their meetings would be a little, much for Arminus. The demon would get carried away and restart him at the bonfire. But that didn’t bother him, if he got his souls back, hollow or human the demon appreciates its new loyal friend. And Arminus appreciates its too. Knowing this the turnout of this boss upgrade is a real success.