One time, when my parents went on vacation, they left my older sister in charge of me. She wasn't too thrilled about it, because she had a boyfriend and wanted to spend Saturday night with him at his family's cabin by the lake, but she knew that if she left me alone, I'd go out dating, which my parents didn't want me doing if they weren't home. We fought about it all week, but I knew I had the upper hand, since she couldn't make me stay home without giving up the weekend with her boyfriend. When I told her as much, she just grinned nastily and said, "We'll see about that."
Anyway, it was early Saturday evening, and I was taking a shower. My sister was working at the chemical plant in town then, in the lab that developed new products, and she'd said she had to go in to do some extra work, so I was alone at the time. She still hadn't told me if she was going to stay home, or go with her boyfriend, but I was going to get ready to go out anyway.
I took a good, long shower, then, when I got out, stood for a minute admiring myself in the mirror. I've got a pretty good build--I'm not too thin, and maybe my belly's a little rounder than it should be, but my breasts are a nice size and my legs are shaped nicely, too. My brown hair just brushes my shoulders, and I've got a friendly face, or so I think. Naked except for a towel wrapped around me, I headed down the hall to my bedroom.
As I entered my room, my eye caught something on the floor. It was a twenty-dollar bill! I couldn't remember dropping it, so I bent over to pick it up. As I did, somebody suddenly grabbed me from behind! I dropped the towel and tried to struggle, but whoever it was was too strong. I felt my butt-cheeks being pried apart, and then, suddenly, something long, thin and smooth was shoved deep up my ass! Whoever was holding me let go, and I stood up and turned around to see what had happened. There was a thin plastic hose coming out of my butt. I tried to tug it out, but it was jammed in tight. It ran along to floor to a big metal gas cylinder, with my sister standing next to it, where I wouldn't have seen them as I came into the room.
My sister was grinning in a really nasty way. She said, "I warned you I'd figure out how I could keep you from getting in trouble this weekend. This cylinder contains a new, experimental gas we just developed in the lab. What I'm going to do is, I'm going to inflate you. I'm going to blow you up so big, you won't be able to get out the door." And with that, she twisted the valve on top of the cylinder all the way open.
With a loud hiss, the gas began rushing into my body. All at once, my skin felt tight all over, and I looked down and saw myself getting plumper. The pressure felt strongest in my belly, and I began rubbing it as it began to bulge outwards. My belly grew fatter and fatter, until I began to look pregnant, and then, even bigger than pregnant. In less than half a minute, my belly was the size of a beachball, with a curve that started just under my breasts and running down to my crotch. Then my sides began to bulge, and the gas spread to my butt, which got rounder and wider, and then down my thighs, pushing my legs apart. My breasts really didn't grow; they just stood straight out, and I almost felt like crying when they began to get stretched flat against my swelling belly.
By this time, my whole middle, from my neck down to my crotch, had become almost perfectly round. My arms were sticking straight out as I continued to fill. Then my shape really began to change. As my body got bigger and rounder, it began swelling over my arms and legs. I could feel my thighs disappear, and I had trouble standing once my still- inflating body reached my knees. I turned my head and watch how my shoulders were stretched, how my arms were becoming cone-shaped as my body overtook them. And still I was blowing up.
All this time, my sister was watching me critically. She would walk around me, patting me to judge how tight I was, saying things like, "You've still got a ways to go, I think you can take even more." It felt weird, her hand on my enormous, curved body, pressing against my tightening skin. Suddenly, I felt a extra-tight pressure on the middle of my belly, which suddenly relaxed. My sister laughed and said, "Your belly button just popped out; I guess that means you're done." So she shut off the valve on the gas cylinder, which must have been almost empty by then. Then she went behind me and jerked out the hose. I thought maybe I'd deflate, then, but I stayed just as big and round and tight as before.
My sister walked all around me again, smiling her nasty smile. I turned my head to follow her, and tried to take a few tiny steps, but I had been blown up so big, my feet stuck out just as far as my ankles. I flapped my hands, which stuck out at the wrists, as if that would do any good. My sister said, "That ought to hold you for a while. You look so full and tight, I'll bet I could bounce you like a ball. By tomorrow morning, when I get back, the gas will have migrated out through your pores and you'll be back to your normal size. I don't think I have to worry about you getting into any mischief now." And then she dragged the gas cylinder out the door and slammed it behind her.
I managed to shuffle my feet enough so I could turn myself to look at the full-length mirror on the opposite wall. When I saw myself, I was too astonished even to cry. I had been turned into a human blimp. My body was immense, an enormous, flesh-pink sphere, nearly as wide as it was tall. My skin was shiny and flushed, from being stretched to such an extreme, and my nipples were just two dark red-pink disks on the surface of my vast, curving belly. My protruding belly-button stuck out like a thumb-tip. Otherwise, I was perfectly smooth all over, except where my hands and feet stuck out. It was so weird, knowing that my vagina was down around my ankles, only inches off the floor.
From downstairs, I could hear my sister close the front door, start her car and drive off. I began to cry then, feeling utterly helpless. I was trapped in my room, blown up to an enormous size, scarcely able to move. And then I heard a tapping at the window! I knew at once who it was. It was Matt, a guy in my class I really liked. We had arranged it in school on Friday that he would sneak over to my house tonight, get the ladder from the garage, and climb up to my room. That way, if my sister had stayed home, I could have snuck out. Before I could say anything, he'd slid open the window, clambered into my room and stood, mouth hanging open, at the sight of my huge, shiny-pink blimp-body.
I stared back at him, ready to start crying again if he freaked out, or began to laugh, but instead, he just closed his mouth, stepped a little closer and said quietly, "Is this really you?" And he slowly reached out to brush his fingertips against my immense, swollen belly. His face was full of awe and wonder.
I was so surprised at his reaction, I almost couldn't speak. Then I found my voice and told him about what my sister had done to me. As I spoke, I began remembering how Matt always kidded my about my being too skinny, joking about how he liked women a little rounder. Well, they don't come any rounder than me! When I was finished, Matt slowly walked around me, and I could see the bulge growing in his jeans. He said, "Sarah, this is my biggest secret, but you look like what I've always dreamed of." And he bend down and kissed my belly button.
I gasped, as waves of pleasure ran through me. I felt my taut skin twitch and ripple slightly. Matt ran his hands over me gently, tracing the immense curve of my body. I began breathing hard; it was like my skin had become super- sensitive from being stretched so much. Most of all, since I was so tight all over, every time he touched my I could feel it in my vagina. I was starting to get wet; I was dripping onto the carpet beneath me. Without saying a word, Matt began taking off his clothes. I gasped again; his erection stood straight out and looked as stiff as steel. He spread his arms and hugged me as best as he could, and feeling his warm, muscular body against me, pressed against my vastness, almost made me come.
He placed both hands on me, then rolled me slightly forward onto my belly. At first I was a little panicked-- once I was off my feet, I was really helpless--but then he began kissing and nuzzling my nipples. I could feel them tighten and try to stand up, as they grew hard I could feel it all the way down to my clit. Then he rolled me forward even more so he could kiss my on the mouth. Between our passionate tonguing, I whispered to him what I wanted. Matt stepped back, took hold of me again, and rolled me backward. When I was facing the ceiling, he stepped behind me. I shivered in anticipation as he took hold of my ankles, and cried out as he brushed against my pubic hair. I imagined my vagina as a pulsing, purple slit in the great bulge of my body, aching for him. Then I felt the probing tip of his penis against my labia, and as he entered me, I screamed for joy. Waves of pleasure radiated out from a vagina that had been stretched and compressed in unimaginable ways. My tight, shiny skin ran with perspiration as Matt thrust into me, bouncing me against floor like the enormous ball that I was. I bulged and stretched with each thrust, feeling his body curved against the distended arc of my body, wishing I could swell even more so I could have even more surface for him to pleasure. Then, at last, I felt his body grow rigid, his penis grow even stiffer, and I felt the pressure within swell even more, and as my skin grew hotter and moister I could feel myself begin to grow bigger. I was swelling out of control, Matt holding onto my still-inflating belly as I lifted him off the floor. I could feel the furniture being pushed aside by my unstoppably ballooning body, and just as my belly button brushed the ceiling, an immense shudder ran all through me, through every inch of my vast, swollen, spherical body, across every inch of gleaming skin stretched beyond any known limit, as we both came.
* * * * *
After our orgasms, I slowly returned to my earlier size, like I had been right after my sister had inflated me. Matt climbed up on my belly, then, and fell asleep on top of me. It felt so nice and warm, having him curled up on me, as if I were some great, living air-mattress. During the night, the gas began to leave me, and by early morning, I was back to my original size and shape. Now Matt felt heavy on top of me, so I woke him with a kiss and warned him that he better get out before my sister got home. After he left, I found myself feeling sad--could I ever again experience that level of pleasure in a normal body?
When my sister got back, I pretended to be sorry, but she didn't say anything--I think she'd had a fight with her boyfriend. And when our parents got back, they decided I go dating any time I wanted. A couple of weeks later, Matt and I were in his car, parked on the ridge overlooking the town. It was our first date since I'd been blown up, and we felt a little awkward. We started necking, and it felt nice, but it wasn't like it was before. I began to think about how it had been, with my body swollen into an immense, round shape, a shiny globe of pink, sensitive skin--and I opened my eyes wide as my clothes began to get tight!