Deep-sea daredevil

Goggles, swim trunks, a stopwatch, an excessively heavy weight belt that could be tightened with (and only loosened by) a specific key... Legoshi had everything he needed for this weird challenge he'd somehow been convinced to undertake. Well, not really somehow, he knew exactly what had happened: In a conversation with Jack and Louis, he'd mentioned offhandedly that he once held his breath for 40 minutes, and, after proving to them that that really was something he could do, they'd started pushing him to see what his limit truly was. Eventually, they'd settled on what Legoshi was currently mentally preparing himself for; with the weight belt on, he'd walk out into the ocean as far as he could, with Jack and Louis swimming above him, then when he felt he couldn't hold on any longer, he'd signal one of them to help remove the belt so he could get to the surface. It sounded reasonable at the time, but now that Legoshi was standing at the shore, the water at his ankles, he found it hard to convince himself to actually go through with it.
Jack and Louis were a distance ahead of him, not far from the point where they'd have to swim to keep their heads above the surface, and starting to get impatient. "Come on, Legoshi, we've waited long enough for this already!", Louis complained. Jack was more encouraging about it, saying "You got this, man! We'll be with you the whole way! Other than when we need to breathe, I guess." Legoshi sighed and decided to finally get on with it, putting on and tightening the weight belt, wading forward as he did. He handed the belt's key to Jack, and as the water reached his chin, he lowered his goggles over his eyes and did his best to relax for a moment, taking deep breaths.
This feels like a bad idea... But, even I'm curious how far I can push myself.
With one last gasp, Legoshi took another step forward, puffing his cheeks as the water overtook his nose and forced him to hold his breath. At the same time, he reached for the stopwatch around his neck to start its timer, and looked to his sides to see Jack and Louis diving under with him. He smiled, then looked forward again to focus on the long walk ahead.

The first 10 minutes were uneventful, the only audible sounds being that of bubbles as the trio progressed along the seabed. Eventually, Jack spoke up. "Stblill dobling alblrigblht, Leblgosblhi?" Legoshi gave him a smile and a thumbs-up, not wanting to waste air on a verbal response. Jack turned to Louis, who'd been trying to walk alongside Legoshi, but found that without as much weight he couldn't go as fast as him, so just went back to swimming. "Whblat ablout yoblu?"
"Kbl-kiblnd oblf nebled aiblr...Fiblne foblr abl biblt loblngeblr..."
"Mmh...Mble toblo."

After another couple minutes, the strain of Jack and Louis had become audible as subtle grunts, and Legoshi started not only feeling an urge to breathe, but a pressure starting to build in his rear. Agh, damn it, not here! He was going to end up farting soon, and he could only hope he'd find some way to keep the others from noticing. Before long, he got his wish, as Louis started swimming up. "Obl-onble seblc, gobltta brbleatblhe." And, Jack followed suit. "Dbl-dobln't woblrry ablout ubls, jbl-jublst keblep gobling!" Watching them swim away, and holding back a sigh of relief, Legoshi relaxed himself.
brlurblrblrt
A cluster of bubbles bursted from his butt, quickly floating away. Jack and Louis would probably see them, but since they hadn't seen where they'd come from, Legoshi would likely be able to pass them off as something else. Soon enough, the two rejoined him, and indeed, Louis was suspicious. "Whblat wabls wiblth thblose bublblebls? Dibld soblmetblhinblg hblappblen?"
Legoshi felt it was worth using some air to respond this time. "Trblippbled."
"Yeblah, wablkinblg doblwn hblere ibls prblettbly awblkwablrd. Jublst, trbly tblo ble moblre cablrefblul."
Jack was a bit confused at this, looking back at Legoshi's footprints in the sand and not noticing anything different about any of them, but decided to just let it go for now.

Only a minute or so later, Legoshi could feel another fart building up, and with no chance of the others leaving for air so soon, he decided to just try to hold it to avoid embarrassing himself. The feeling didn't go away, though, and in fact, over the next few minutes, it actually grew. Eventually it reached the point where the pressure caused a few bubbles to slip out, making Legoshi blush heavily and clench his butt to keep it from happening again. It worked for a while, but after another couple minutes, his belly started to cramp a bit. Rubbing at it to try to ease its pain, he noticed that it seemed slightly bigger than normal... It soon occurred to him; the gas building up in him was actually starting to slowly bloat him out! Even with that happening, though, Legoshi continued to hold it in, but as the pressure kept building, he started letting out tiny farts despite his efforts. Soon enough, he was leaving a constant thin trickle of bubbles behind him, and Jack and Louis quickly took notice, with Jack being the first to say something. "Yoblu okblay? Hblow coblme yoblu're fablrtinblg sblo mublch?" Looking over at him, face red with strain and embarrassment, Legoshi figured there was no point in trying to hide it any more, and let loose.
BLRURBLURLUBRLBRULRBLRBRLBULRBLRT!
For nearly 10 seconds, a massive cloud of bubbles erupted from him in a single enormous fart, his belly quickly returning to its normal size. It was clear that Jack was trying not to laugh, but this time Louis was the one to be more supportive. "Yoblu...Reblallbly shbloulbldn't hblold ibln thblat mublch, yoblu're stblraiblninblg yoblursblelf foblr nblo reblasobln." He had a point, using so much effort to hold in his fart had wasted a fair bit of oxygen, and he needed everything he could get for this. With a nervous smile, and somewhat less embarrassment, Legoshi nodded and continued onward.

27:52, the stopwatch said. Legoshi's chest had started lightly contracting, his cheeks getting a bit bigger, and the others had gone for air again. "Mmnh...blrbl..." He blew a few bubbles to try to ease his urge to breathe, though quickly regretted it, starting to blush from strain. Still, though, he wasn't planning on giving up anytime soon. Jack and Louis returned, and Jack had good news to share. "Ibl thblink webl're abl mible oublt, noblw!" Legoshi grinned and raised a fist in a silent celebration, with Louis seeming pretty impressed. "Iblt ibls wibld thblat yoblu cabln hblold yoblur brbleatblh sblo loblng, hblave yoblu alblwaybls beblen liblke thblis?" He just got a shrug in response, and the trio continued.
As the 40 minute mark came, Legoshi was really starting to struggle, his cheeks at the size of basketballs and his blush having turned purple. "Hmrgh, Mmm!" For another few minutes, he pressed on, but as his lungs started to burn, and he passed his breath holding record, he finally wanted to give up. Legoshi looked at Jack and pointed to the weight belt, trying to make it clear that he wanted to end this challenge. Jack just shook his head. "Coblme obln, yoblu cabln hblandble abl whblile loblngeblr, cabln't yoblu?" Legoshi's eyes widened, and he too shook his head. He probably could hold his breath quite a bit longer from here, but this wasn't fun any more, and he was starting to worry about potentially drowning. Louis seemed to share Jack's opinion, "Whblat bebltteblr wably tblo fiblnd yoblur liblmit thblan tblo keblep publshiblng yoblu?"
Legoshi panicked and tried to swim up a few times, barely getting anywhere before the weight belt made him sink back down each attempt. Then, he tried to pull off the belt for a minute, but it was tight enough that he couldn't even move it. He looked at Jack again with fear in his eyes, though he clearly wasn't going to be helping. "Iblf yoblu reblallbly wablnt tblo brbleatblhe..." Jack gestured to Legoshi's footprints off in the distance. "Yoblu'd bebltteblr geblt moblvinblg!" Without hesitation, Legoshi started sort of swim-jogging back the way he came, covering his muzzle with a hand.
Gas was building up in him again, but he didn't care this time, ignoring it completely. Soon, the bubbles from his nose were joined by small groups of bubbles from his butt as he repeatedly farted. Jack finally laughed out some bubbles of his own at this, saying "Thble hblell dibld yoblu eablt, anblywably? Thblis ibls ribldicbluloblus ablt thblis poblint!" Legoshi just ignored him, his only concern being getting to the surface, glancing at the stopwatch to see he'd been underwater for 48 minutes. Despite the situation, he found himself starting to get aroused from holding his breath so long, a bulge forming in his swim trunks. Why am I getting hard!? This doesn't make sense!

For another 10 minutes, Legoshi ran along the seabed, eventually getting tired and slowing to a walk again, still occasionally farting out bubbles as his cheeks continued inflating, now 3 feet wide. With his dick so hard it was aching, he couldn't resist reaching under his trunks to jack off, lightly moaning despite the situation. "Nnmmblrburbl..." Louis chuckled at this. "Yoblu ceblrtablinlbly loblok liblke yoblu're enbljoybling yoblursblelf. Shbloulbldn't yoblu foblcus obln geblttiblng bablck tblo thble shblore?" Legoshi whined and started walking a bit faster, his blush now starting to turn blue.
3 more minutes, and he stopped and stiffened, his masturbation speeding up. "Mmmblurblablulg...", he went, cheeks deflating some and his dick throbbing hard, cumming through his trunks as his eyes rolled back. Briefly forgetting the situation, Legoshi weakly smiled and humped at the water as he came, then quickly remembered how badly he needed air, putting both hands on his muzzle and finally continuing. His cheeks returned to their size from before his orgasm and started expanding much more quickly than before, gaining an inch every few seconds. Jack and Louis found themselves dumbstruck with how enormous Legoshi's cheeks had become, and looked at each other. "Thblis mublst ble abl neblw thbling, hble wobluld hblave meblntiblonebld thblis", Louis said, and Jack nodded.
Another couple minutes, and Legoshi's cheeks were now big enough that they actually started to touch the ground! Not long after that, he froze up again, shivering with another few bubbly farts, then...
"Slrp-GLP!"
Reaching his breath holding limit, his mouth opened in spite of his grip, and he sucked in some water, managing to swallow it before it got into his lungs. His cheeks rapidly deflated as he involuntarily blew out a lot of air, quickly returning to just a couple feet in width, then he sucked in and gulped again. And again, and again. Soon, Legoshi's desperate drinking of seawater turned to full on chugging, and adrenaline surged through him as he took off running again. Jack and Louis had been catching their breath at the surface and ended up missing the start of this, much to their frustration, but managed to keep up with him.
"Hlp-glp, slrp-ulp, huulp!"
Legoshi barely noticed in his panic, but his belly had started to expand again as he forced himself to drink the water he was involuntarily sucking in. For minutes on end, each instinctual gasp continued to be interrupted with a swallow, his blue blush beginning to spread over his face and onto his still-puffed cheeks as his arousal rapidly built up again. Louis looked over at Jack. "Mablybe thble fablct thblat hble cabln inblflablte liblke thblis hblas soblmetblhinblg tblo dblo wiblth hblis brbleatblh hbloldbling?" Jack just shrugged in response.
Eventually, as Legoshi's belly became several feet wide after a total of 9 minutes of gulping, something started to change. "Slr-hrkgh...Gulp! Hlp-khk...Ulp!" He was just about full, and it was now a struggle to keep swallowing after every attempt to inhale. Finally, he couldn't manage to force down another gulp, gagging as the water caught in his throat. Legoshi fought it as best as he could, but there was only one place the water could go, now.
"Ghlk! Ghkhkh! GHGH...G-GHHUUUUAAAGLKGAGL!"
Grabbing his neck, he froze once again, holding in this breath of water. For almost 10 seconds, he stood there stunned and silent, not even any bubbles leaving him. Then, finally, his mind caught up with what was happening.
"GLURLGRL, HUUUAKH! KAGRULBLRBL, HUUAA!"
Doubling over (at least, as much as his packed belly would let him), Legoshi loudly choked and gurgled, drowning hard as he came for a second time. Jack looked down at him nervously. "...Ublmm...Wble knblow hblis liblmit noblw, shbloulbldn't wble hblelp hblim?"
"...Noblt yeblt. Whblen hble pablssebls oublt, wble cabln jublst sqblueeblze thble wablter oublt oblf hblim anbld giblve hblim CPblR, thble shblorebl's prblettbly clblose.", Louis responded, though he felt there was a chance Legoshi could get to the shore on his own, if he could handle breath holding for so long.
As he'd fitfully gasp water and cough it back out, Legoshi looked up at Jack and Louis. "GRGLK! FF-FUGHCKHING D-HUUAKH! D-DO SSOMETHHUUINGH!" Jack felt terrible for it, but tried to ignore him, wanting to go with what Louis had said. Seeing he still wouldn't be getting any help, Legoshi started running again, his huge gut making that somewhat difficult, as he held it out of the way with one hand, keeping the other on his neck.
After a few minutes of choking, he finally started to calm down, his desperate gasps turning to heavy panting, then slow, calm breathing as he stumbled forward. The shore still wasn't visible to him, and he just continued to follow his old footprints. "...hhuuuhhh...bluuuhhh...hhhuu-hicp-blughh..." He started to hiccup, and each one seemed to be quickly followed by a weak fart, which were the only source of bubbles from him at this point. As Legoshi eventually passed into his 7th minute of water breathing, the shore finally became visible, with Jack and Louis themselves actually starting to get purple blushes, so impressed by their friend that they tried to ignore their own need for air, not wanting to miss any of this.
"...glrg....hh....h......" Legoshi's drowned breathing slowed to a stop, though he remained barely sleepily awake as he very slowly walked up the slope to the surface... Which, he reached! Only, he still didn't attempt to breathe, and after a few awkward steps, he collapsed forward onto his huge belly, the impact forcing him to spit up some water. He'd happened to get far enough that his head was above the water like this, so as soon as he'd remember to breathe, he could recover.
Jack and Louis surfaced, gasping hard and running over to Legoshi. "Wake up! You're so close, just breathe!" Jack said, patting Legoshi's back. Louis held Legoshi's head to try to get his attention, glancing at the stopwatch at the same time, saying "We'll give you CPR if you pass out, but I really want to see if you can recover on your own!" Legoshi gurgled a bit in response, some water pouring from his mouth, then finally, barely inhaled. "....ghhiihh..." Awareness slowly returned to him, and soon enough he was hacking and gasping as he slowly recovered, the blue tint fading from his face.
When he finally recovered to a reasonable degree after almost 10 minutes, Legoshi, Jack and Louis were sitting on a dry section of the shore, with Legoshi still having quite a lot of water in his gut, and complaining to the others. "What the fuck is with you guys!? Why the hell did you just let me drown?"
Jack gave him a guilty look. "...I-I'm sorry.. .We wanted to find out for sure how long you could hold your breath, and we got kind of... Carried away, I guess."
Louis put a hand on Legoshi's shoulder. "I'm the one that put him up to it. Honestly, I really shouldn't have, I feel awful for that."
Legoshi sighed and shook his head. "God damn, you guys... We could've just used, like, a bathtub or something, if that's what you wanted."
They sat in silence for a moment, then Legoshi remembered he was still wearing the stopwatch. "...Did either of you happen to catch what the stopwatch said, when I got to the shore?"
Louis grinned. "I did. You were definitely drowning for a lot of it, but... An hour and 21 minutes."
"WHAT!?"