Bubbled showtime

There was quite an assortment of rather strange objects in the bathroom the Ducky and Strut were in: A chair, a long pole, a couple ropes about 5 feet in length, an air tank, and a weird-looking machine of some sort that had a large bubble of water growing from one side, a hose from the opposite side connected to a nearby faucet. Ducky was currently looking over everything but the chair, stepping on one end of a rope and pulling the other to test its durability, as Strut leaned on the back of the chair. "Don't worry about checking all those out, I've tested them myself like 3 times, even practiced pulling stuff with the ropes."
"I know, this just... Makes me feel more sure about this."
Some time later, as the water bubble reached a satisfactory size, Strut turned off the faucet and the machine, then turned to Ducky. "Right, whenever you're ready." She nervously walked up to the edge of the bubble, looking up as it towered over her small body, then looked back at Strut who'd sat down in the chair. "...C-could we go over the plan, one more time?"
"I mean... You're stalling, but sure. Once you've hopped into that bubble and shown off for me for a while, I'll pull you out with the pole. If that doesn't work for whatever reason, then I try the ropes instead. If that somehow doesn't work, I'll toss you the air tank and we'll figure something out from there, but I'm almost certain it won't come to that."
Ducky nodded, then looked at the water bubble again, taking deep breaths both to calm herself down and prepare for a long breathhold. Finally, with the biggest breath she could manage, she puffed her cheeks and jumped forward, slipping into the bubble and floating in place for a moment before slowly starting to rise, swimming a bit to keep herself in place.
Strangely, now that she was underwater, Ducky felt a lot more confident, and turned to face Strut. "Beblen plblannbling whblat tblo dblo foblr thblis foblr abl whblile, Ibl beblt yoblu'll liblke whblat I'vble goblt ibln miblnd..." Strut had moved the chair up next to the edge of the bubble and started jacking off, watching Ducky blow out bubbles as she spoke. "Even you just being in there holding your breath is hot... Are you planning on pushing yourself?" Ducky just nodded, blowing more bubbles and turning around, pressing her butt against the water bubble and smooshing it around a bit. She started floating up again, and decided it would be best to counteract that early on, opening her mouth to start drinking at the water and reduce her buoyancy without wasting air. "Glp, glug, glp"
Strut's eyes went wide and he blushed heavily at this, staring at Ducky's slowly expanding belly. This was certainly a reaction she hadn't anticipated, so she decided to deviate from her plan somewhat, turning so Strut was on her left and would have a good view of her belly, starting to swallow more forcefully to inflate herself with water more quickly than before. "Gulp! Ulp!" As her stomach became about a foot wider than normal, she decided that would be a good size for now, jiggling it around as she faced Strut again, now able to stand on the floor. "Ibl jublst stblartbled drblinkbling sblo I'bld siblnk, dibldn't thblink yoblu'd bble thblis inblto iblt!"
"Not so much the drinking, you just look great with a big belly!"
Ducky smiled and puffed her cheeks back up, laying down on her side and blowing more bubbles, occasionally smacking her belly to make it wobble around a while. Eventually she turned onto her back, continuing to bubble, even managing a few bubble rings as she began to blush from the strain in her chest. Strut, of course, was loving all this, especially as he started to see Ducky's chest heave from the lack of air. "Ffuck, this is even better than I was hoping..." Then, under his breath, he added, "And it'll be even better soon enough..."

With another couple minutes of Ducky's carefree bubbling, the urge to breathe started to be a bit of an issue. "Blublubl-Mmm!" She sat up and covered her mouth, glancing over to Strut, who'd stopped jacking off for the moment. "Oh, need air?"
"Mmhm!" Ducky nodded.
Strut smirked. "Do you want air?"
Ducky mirrored his expression and shook her head. "Mm-mm."
"Hell yeah. And hey, if you push yourself to the point that you start gasping, I can just throw you the air tank!"
Standing up again, Ducky put her hands behind her head to show off her slowly intensifying breathless twitches, little grunts being audible to Strut outside the bubble as her cheeks started to visibly expand. "Mmrk...Mnph..." He, of course, had started masturbating again, also deciding to hold his breath alongside her. The blush on Ducky's face started to turn purple, and she started fingering herself to try to hold on longer.
Ducky's cheeks were each now about as big as her head, her blush turning blue as her eyes rolled back, getting worryingly close to her breathholding limit as the bubbles leaking from her nostrils started to dwindle. Strut was still holding his breath as well, though he couldn't last as long as Ducky could, already straining hard before deciding to just exhale and breathe normally. The arousal of both dinos finally reached its limit, and the two came at almost the same time, Strut being first by a moment.
"Dh, D-Ducky... Ghaaaah!"
"Mmmblgagblabagl!"
Ducky's juices spurted into the water, and Strut's cum splattered onto the bubble, both of them forgetting about how badly Ducky needed to breathe for the moment. It wasn't long before they remembered though. "HMRGH!" Ducky instantly covered her mouth again, fearfully looking at Strut as her cheeks inflated even more. "G-GEBLT MBLE OUBLT!"
"O-okay, I got you!"
Strut pushed the chair aside and grabbed the pole, sticking it partly into the bubble for Ducky to grab as he tried to pull her out... But, the smooth material the pole was made of caused it to slip out of his hands, ending up getting stuck in the bubble itself. "Damn it! A-alright, the ropes, then!"
Ducky whined as her lungs started to burn, holding onto the end of a rope Strut threw in... Once again, the rest of the rope flew from Strut's hands and into the water bubble. "F-fucking come ON!" Curling inward as much as her bloated belly would let her, Ducky tightly shut her eyes and didn't immediately notice the second rope's end being thrown in. "GRGH! HMBLP, BLRGL!" This was the longest she'd held her breath, and it felt to her that there were only a few seconds left before she'd be forced to breathe. "Ducky! Get the damn rope!" Jolting back to awareness, Ducky grabbed this second rope... This time, Strut slipped on the floor and fell, with the same end result as the last rope. "Ghah! J-just... Here!" Strut threw the air tank into the bubble, and Ducky scrambled to grab the mouthpiece, feeling like she was at her limit as she finally...
Didn't get any air. She sucked harder on the mouthpiece, but still, nothing happened. The tank was empty. Panicking, she looked at Strut, seeing he was moving the chair back to where it had been when she'd been showing herself off. Then, instead of doing anything to help, he just sat back in the chair! She wouldn't be left confused by this for long, as Strut made his intention clear. "I'm a pretty good actor, huh? You had no idea this is what I was planning!"
Ducky whined again and started to shiver as she gulped a bit of water that slipped between her fingers, while Strut continued. "I never intended to get you out of there. All my "mistakes" in rescuing you, I did on purpose. Even made sure to drain that tank. All that's left now, is for you to give me an even better show~"
Beating against the bubble's edge, Ducky tried to force her way out as bubbles streamed from her lips, her cheeks getting to an even more ridiculous size. "BLBLPH, HBL-HBLELP! MMMHU-GLP!" Sucking in some water and barely managing to swallow it, she covered her mouth again and checked what Strut was doing. He was still just sitting in the chair, though he'd started jacking off again as he watched her fight not to drown. "Go on, then", he said. "Breathe it in".
It didn't seem like it would be long before she would be forced to do so, but Ducky continued to hold on as well as she could, not quite able to stop some water from slipping into her nostrils, but at least managing to swallow it. Soon enough, she couldn't hold her breath any more.
"Mm, MM, MMMMBLULBLBLGHABLABL! GK, GHUULP!" 
She may not have had any meaningful amount of air left in her, but she just barely managed to swallow the water her instincts forced her to suck in. Then, another gasp and swallow, and another. Repeatedly hiccupping and gulping water, Ducky's belly started to inflate even more (much to Strut's pleasure), her blue blush spreading across her face and the rest of her starting to tint blue as well.
Smacking at the bubble again, Ducky tried to yell something, but couldn't say anything with her lungs completely empty, and just gulped a couple more times. Strut laughed at her. "Can't really talk with empty lungs, you moron. If that was what that was, anyway. Not sure it would work, but maybe you could talk with water in your lungs?"
Shuddering, Ducky slowed down for a moment, her belly having gotten another 2 feet of width since she'd started this bout of gulps, and she sucked in again. "nh...ghuuup...HRGLK!" This time, in her drowsy state, she forgot to swallow, and ended up inhaling about half a lungful of water. Immediately she covered her mouth again, desperately shaking and staring at Strut as she held in the water. "Oh shit, did you just breathe? Damn it, I missed it!" Ducky ignored what he said, frantically kicking about and doing everything she could to hold in this breath that was changing absolutely nothing. She didn't get any height with this, sinking to the floor because of the water in her stomach and chest.
Despite the situation, Ducky was rapidly getting aroused as water sloshed and stung at her lungs, though she resisted the urge to masturbate. Soon enough, though, her arousal built to the point that she had an orgasm anyway. "nNGUUAARGLRGL-HUUAAA!" Now, she was truly drowning, thrashing and spurting some more, rapidly gasping so loudly that Strut, still jacking off, could hear it. "F-fuck, you're... Sso hot, Gah!" He came for a second time, shooting more cum onto the water bubble. Ducky paid that no mind, still writhing as she choked on the water, managing to get up and stumble toward Strut, pressing a hand on the bubble's edge and holding her neck with the other. "URGL, HHELP! D-HICP! D-DROWNHING!"
"I know, it's awesome! You look great in there!"
Once again seeing that Strut still wouldn't help, Ducky tried to push the water bubble toward him, though its weight prevented that. Strut scooted his chair back a bit in response. "No way am I touching that thing. Not risking getting stuck in there with you." Ducky attempted to shove it at him a couple more times, her gurgling seemingly more angry than pained for a moment, than tried to grab the edge, which took a few attempts as it kept slipping out of her hands. Finally getting a grip on it, she tried to pull the bubble apart, but only ended up stretching it out, eventually even pressing it against her face and blocking her water breathing as she stretched it out further before it slipped away again.
Thinking she'd been close to accomplishing something, Ducky decided to try grabbing the bubble's edge again, but this time she reached for the top of it, still a couple feet away with her arms fully extended. Jumping off the bottom, she only got most of the way there, trying as hard as she could to swim up the rest of that distance, but only very slowly gaining height. After nearly 20 seconds of desperate swimming, Ducky started to slow down, quickly landing on the floor again, then just repeatedly hopping up and down as she now lacked the coordination to even attempt to swim. Her waterlogged belly wobbled around while she jumped, and her gasping was slowing down, soon turning to just slowly panting the water. Eventually, she messed up her landing and fell on her butt, sitting there with a blank expression and lidded eyes for a few seconds, then slowly turning her head to look at Strut relaxing in the chair, still watching her.
With her mind feeling fuzzy, all Ducky could currently remember was that she'd gone into this bubble to show off for Strut, and that was what she would do. Slowly struggling to her feet, she awkwardly stumbled toward him and leaned forward on the bubble. "gluhk...ennjoyyingh...yyourr-hic!-sselfff...?"
"Hell yeah! Keep at it, you blue beauty!"
With a weak nod, Ducky attempted to blow bubbles. She herself could see them floating by her face, though they obviously weren't really there, any air she had being long gone at this point. Stepping back a bit, she started gulping again, making her belly even bigger. "...glp...ghl...hulp..." It wasn't inflating much this time, and after about 30 seconds, Ducky seemed to go limp for just a moment as her consciousness briefly faded, though she managed to recover. Despite feeling to her like she could keep this up forever, she was clearly still very slowly losing energy.
Outside the bubble, Strut was still just relaxing and watching Ducky's waterlogged show. He sure didn't understand how she was able to keep going for long after drowning, but he certainly didn't mind getting even more entertainment out of her before she'd pass out, and scooted the chair closer again.
Losing her balance for a moment, Ducky stumbled back a couple steps, her huge blue belly jiggling around and catching her attention. "...mrgl...hhuhuhhh...huuup..." She gave a gurgling laugh, then took in and held a breath of water, cheeks getting huge once again as she started to smoosh her belly around. Again, though, before long her eyes rolled back and she almost passed out, going "bluuughh..." as she exhaled the water and fell to her knees. It took noticeably longer for Ducky to recover this time, but she still did, and continued to kneel instead of getting up. At this point, she'd even forgotten about Strut, and as she started to feel horny once again, she lifted her gut out of the way to finger herself again.
Strut was getting even more impressed with how long Ducky could handle drowning, but could tell she didn't have much left in her. The lapses in consciousness were slowly getting longer and more frequent... Until, finally, she didn't seem to be recovering from one. Watching for several seconds with no change, Strut stood up. "Guess that's finally it... Totally worth tricking that dumbass-"
"GHUURRGHHK!" Ducky arched her back and gasped loudly as she suddenly, somehow, shot back to awareness! Choking hard, she scrambled to her feet and pressed against the bubble's edge again, juices visibly spurting from her pussy in an orgasm as she'd bang on the edge, now burning through the very last of her energy.
"Ooh, an encore? Sweet!" Strut leaned on the back of the chair, not expecting this to last very long despite Ducky's absurd endurance. Already he could see her starting to slow down again, her punches getting weaker and weaker by the second. Before long, Ducky had gone back into a delirious, drowned state, slumping forward against the bubble and sliding down onto her belly. "Ghuuh! Huuaa...hurgh......" Once again, she went limp, eyes remaining halfway open, her deep blue body continuing to subtly twitch. Strut watched for about 30 seconds this time to make sure she was really gone, and as those twitches stopped, it was clear that she wouldn't be recovering from this one.
Standing up again, Strut stretched a bit. "One hell of a show you gave, Ducky. Almost feel bad that it's gonna be your last." Just before he left, Strut looked back at Ducky's thoroughly drowned body and smiled. "Goodnight, Ducky~" He turned off the light, stepped out, and closed the door, leaving her in darkness.