"MPHH MHPHPH?!?!?"
The annoyance and questioning surprise in Sylvia's face right back at you, was growing more intense by the minute, as by now her cheeks had expanded full of air to the size of softballs, like two ballooning blobs of puffed up consistency, protruding further from her face as the thick hose - shoved deep and tightly in her mouth between them - was forcing endless amounts of pressurized air from the helium tank beside her, into them and down Sylvia's throat, as the gas was quite aggressive in finding al the right spots to bloat up in her already chubby - soon to be quite the ballooned up one - body...
This inflation experiment she had agreed to, was not what Sylvia expected, especially out in the open on a sandy beach and at that time of the day, and since both of you were usually only just playing around with large balloons and air-tanks, while your obsession with this body inflation thing led you to this crazy thought of trying it out on Sylvia herself to be the balloon this time, and without thinking further into it or asking her permission for it, you just shoved the hose from the tank into her mouth and cranked the tank's valve all the way.
The pressure was intense, and even cause Sylvia tried to play along, she was still in distress more and more as the pressure was building up from inside of her and the results on her body were drastic and immediate as her concern grew even more intense, by taking looks downwards to her ballooning body, past the gargantuan expanding cheeks that were blocking her view even more as the hissing intensified as well, making some nearby people on the beach to start and stare at the inflating spectacle as well...
Sylvia's turquoise bikini top, was growing tighter around her upper body, as the strain on it was growing unbearable, with her boobs already blown up to the size of blimps, almost like a basketball each, and her arms puffy and flailing at her sides, while her bottom parts - the most impressive by now - had blown up immensely, with thighs expanded with air to the size of tree trunks stretching her bikini bottom impossibly, her belly like she had swallowed an exercise ball, and overall a backside that resembled some parade balloon's backside, rather than some actual girl's one...
Sylvia's body was resembling a blow up doll that had been inflated far too much by now, and kept expanding and inflating as you were determined to keep that inflation experiment going no matter what the cost, since you were a stubborn horny guy as well, and you were even enjoying this spectacle far to much as to turn off the tank so early...
"MPHMPHH MHPHPHPH MHPHPHPH!!!!!"
Sylvia kept muffling though the thick hose in her mouth, the distress more intense as she got bigger and bigger, still trying to play cool though, trying to hide all her distress while the hissing and clothes ripping sound intensified in the area around her and people were gathering up even more closely to the both of you. Her bikini fell to the sand in shreds as her body was becoming more spherical by now, almost at the size of a large room and she floated softly above the sand, as her boobs were inflated almost to the size of weather balloons and her cheeks had expanded with helium to the size of volleyballs, the thick hose still siphoning endless amounts of pressurized gas within her rubbery body. People were gathering around more and more, snapping pics on their cells, even recording the scene on video, as Sylvia's size was almost as huge as a house by now, and she floated even higher on the sunny beach, casting heavy shadow for more than a hundred people to cool down under...
"MHPHPHP MHHPHPHPHPHHHHH MHPHPHPHPHPHHH!!!!!"
And Sylvia kept screaming through the hose, as by now all her facial characteristics were being stretched on her globular shape, even her lips and eyes seemed puffier as by now her cheeks had expanded to the shape of over inflated beachballs and she kept emerging into the sky above the beach, at a gargantuan size that could easily cover all the length of the vast tropical beach from one end to the other, a serious amounts of miles in diameter, as the poor girl kept inflating and expanding at the tank's mercy with no signs in stopping any time soon...
You smiled at the spectacle above as you just lost track of how serious the situation was and since you were lost in bliss you jut left her inflate larger and larger like the world's largest blimp, people fleeing in fear at that point, as Sylvia started casting her spherical shadow over a large portion of the ocean, the coastline and some of the province as well, now several feet high into the sky, the only thing keeping her from floating upwards, the thick hose still tight in her mouth, as by now her cheeks had begun to merge with the rest of her planetary form, no signs of this being an actual girl since all her limbs had merged completely into her body, only some huge football stadium sized that used to be her boobs, reminding that this was Sylvia and not some parade blimp that had gone completely out of control...
And there, she was still ballooning, and still screaming though the thick hose, not heard by anyone at this height as her ballooned up planetary body, emerged through the clouds into the open sky and started exiting the atmosphere and into the stratosphere, almost the size of a continent in width by now, as that tank seemed to still be forcing endless amounts of helium inside Sylvia's moon-sized body, when...
"POP POP !!!"
Sylvia's eyes puffed out of her sockets and begun inflating on their own since every part of her body was expanding by now, and helium tired to find every last refuge to fill and expand. Her eyeglasses shot away into the open space, as her eyeballs, almost the size of a hot air balloon each, kept expanding and inflating with gas, giving her the goofier look any girl could have at that point, and her whole body started becoming transparent, as she was soon reaching her rubbery limits...
"MPHPHPH PHHPHP MHPHPHPHPH MHPHPHPHPHPHPHPH-------"
"SCABLAAAAAAAAAAAAAAM!!!!!!!!!!!!!"
Sylvia tried to scream one last time, before her planetary sized balloon body, exploded into a billion rubbery pieces, almost sending the planet a little off course, as the powerful explosion sent her shreds to cover almost half the globe, and the hose started falling back into the ground, the gas still forcing itself out of it into the open air, before it landed a few feet away from you, near the helium tank...
"Best balloon popping... EVER!!!"
You yelled in bliss, as a heavy rubber rain of Sylvia's torn pieces, kept falling and covering almost everything on the beach, as well as a vast amount of land on the horizon...