Sibling Influence (Patreon)

Steven sat in his computer chair licking his lips, his cock was already out with both hands wrapped around it and he was rubbing it slowly. Not so long ago Steven had a normal-sized cock and balls. That was until he stumbled across InflatableIncestGal’s DeviantArt page. It was like her artwork was made for him. It played to his every kink. Incest between brother and sister hyper and giga breast expansion, belly expansion, butt expansion, and cock and ball expansion. Impossible insertions, stomach bulging, cum inflation, but most of all lots of passion and addiction to lust and arousal. Not to mention the main characters that were present in most of the comics kinda looked like him and his sister. Only, you know, if his sister was a massive slut with gigantic tits and ass cheeks.  

He didn’t think he could get so horny, but as he looked at the comics InflatableIncestGal made. He found himself getting hornier and hornier and hornier until his cock and balls actually grew bigger. The first time it happened Steven didn’t know what to do with himself. The throbbing was so intense it felt like he was on the edge of cumming the whole time. When he finally stopped growing and he did cum Steven passed out from pleasure the first time. Every day after that he went back looking for updates and new images and he kept growing and growing and growing and growing.  

Steven had become addicted and obsessed with her art by now. He checked multiple times a day and if there was something new, he had to beat off to it right there. That meant if he was in a coffee shop he would go to the bathroom. If he was outside, he had to find some bushes to go behind or something. He couldn’t help it just seeing InflateableIincestGal had uploaded something new was enough to get him hard. He knew now that her artwork was so hot it was literally going to make him so horny it was going to force him to grow bigger. Whether he wanted it or not, and he did, he very much did.  

It was getting to the point now where he wasn’t sure if he wanted to go out anymore. He was more certain that he just wanted to sit in his room and keep jerking off as hard as and as often as he could to InflatableIncestGal’s work. Steven opened his DeviantArt and hit refresh. His pulse quickened, there was some new artwork. Clicking on the image it was like it was crafted for this moment. The sister in the comic was egging her brother on saying things like “come on keep jerking off, I know you want to just keep jerking it harder and harder forever.” Steven bit his lip hard to keep from moaning as he started to jackhammer up and down on his rock-hard, four-foot shaft.  

As he continued to read and look at the pictures, he only got hornier and more excited. It kept mounting and building. The sister in the comic was knocked backward by her brother's swelling cock landing on a hose. As she tried to get off, she realized she was stuck and couldn’t get off all while her already gigantic tits and ass started to blow up out of control. It wasn’t long before her belly joined in. The brother upon seeing this proclaimed she was making him too horny and he couldn’t stop jerking off anymore. His hands and arms wouldn't listen to him; they just kept rubbing harder and harder. 

Steven stuffed his face into a pillow moaning loudly into it to drown out the sound. Yes, he wanted that, he didn’t want to stop anymore he wanted to just keep growing and growing and growing like the brother in InflatableIncestGal’s comic. His cock and balls shuddered and throbbed bigger in his hands as he brought himself to the edge of orgasm: "Yes! Bigger! Grow bigger! I want to grow massive!” Steven rambled into his pillow as his cock stretched out fatter and longer, growing out another foot in length. Steven arched his back, his cock thumping, his heartbeat pounding in his ears as wad after wad of cum burst from his cock. He came and came and came. It was the most intense orgasm to date. Collapsing back in his chair, his chest heaved “ohhhh shit that’s way more than normal,” he grunted. “I’ve never grown like that before,” he said looking up at his girthy cock's head in awe. 

Looking back at the comic, Steven nodded to himself “I’m gonna do it,” he said as he pulled up his keyboard “but I got to let her know what her work means to me first.” His fingers clacked away at the keys as he wrote the following message. 

InflatableIncestGal I just had to let you know that I love your work. No more than love, I’m obsessed with your art. It’s just so hot and sexy I can’t wait to see new work from you. It’s the reason I get up in the morning. I want you to know that every time I see your expansion art it makes me so horny it actually forces my cock and balls to grow bigger. And I love it! I love that your artwork turns me on so much it makes my cock and balls swell fatter and longer. I keep looking at your art for hours on end getting hornier and hornier and cumming harder and harder.  

I’ve decided I don’t want to stop anymore. I just want to keep jerking off to your artwork. I don’t want to go outside anymore. I’m going to drop out of college. I’m going to dedicate my life to jerking off to your artwork. So, I can keep getting hornier and hornier and hornier and hornier! I promise I’m going to go back and jerk off to every last one of your pictures. I’ll make sure my cock and balls keep growing and growing and growing. I’m never going to stop rubbing it god I wish you were my sister I want to do all those nasty things you’ve drawn to you. My hands are shaking, I’m so excited. I know this is what I want. I've never been so sure of something in my life. Keep an eye out your window because one day you might just see my cock and balls looming on the horizon. If you do know that you caused it! You and your sexy artwork.  

Steven hit the send button and then quickly started scrolling through InflatableIncestGal’s gallery making his way back to her older artwork. A loud moan came from next door in his sister’s room. Steven froze in his tracks “holy shit is she masturbating?” his heart started to race, his cock grew painfully hard. There was a ding from his computer InflatableIncestGal was messaging him directly. His mouth went dry, but his hands started to sweat. There was no way she was actually talking to him. He opened the message.  

InflatableIncestGal: Did you really mean it?  

ExpandableIncestFreak: Did I mean what? 

InflatableIncestGal: That you would fuck me if I was your sister? That my art really turns you on that much? 

ExpandableIncestFreak: I meant every word. 

InflatableIncestGal: Are you jerking it now? 

ExpandableIncestFreak: Not yet, but as soon as I’m done talking to you, I’m going to start and. Never. Ever. Stop.  

There was another moan from the other room.  

InflatableIncestGal: So, you would have sex with your sister? 

ExpandableIncestFreak: .... Yeah, I would. 

InflatableIncestGal: You think she’s sexy? 

Steven paused; he had been mostly humoring InflatableIncestGal. Though now, as he thought about it, yeah, he did think his sister Florence was sexy. She wasn’t particularly curvy, but she was beautiful. He thought about his cock siding into his sister Florence, stretching her out. He couldn’t help but let out a groan.  

ExpandableIncestFreak: Yes, my sister is ridiculously hot. It’s kinda funny the way you draw your Terra character kinda reminds me of my sister. Maybe that’s why your artwork makes me so horny. It lets me fantasize about fucking my sister if she had massive sexy balloon tits, ass, and belly.  

There was some thumping and more moans from Florence’s room. What was she doing in there? Steven wondered to himself. They were siblings, maybe they had similar sex drives.  

InflatableIncestGal: Have you ever tried? Made a move on your sister? 

ExpandableIncestFreak: No, there’s no way I could do that. I’m a freak I know, but she’s not like that. 

InflatableIncestGal: How do you know? How do you know she’s not just as much of a freak as you are? How do you know she’s not in her room right now? Playing with her gushing pussy thinking about how much she wants to get fucked by her brother? 

Steven gulped. This was getting intense. He had never grown without looking at InflatableIncestGal’s artwork before. This exchange got him close though, he could feel it. The same pressure was mounting in his cock. This time it was a slower, more methodical build-up, but the feeling was still there. 

InflatableIncestGal: I have something to show you. 

Steven’s mouth fell open slightly as he leaned in closer to his screen in anticipation. A link popped up on screen to a google drive. Steven clicked on the link. It was InflatableIncestGal’s gallery only he could see that the names of the siblings were different. Normally their names were Rebecca and Bobby. Only in these versions of the pictures, it was his name and Florence’s name being used. “Holy shit!” Steven breathed. There was another ding. 

InflatableIncestGal: I want you, Steven. I always have. I found out about your inflation fetish and your incest fetish when we were younger. Turns out we’re remarkably similar as I was turned on by it too. Especially the part about fucking you. Reading your username, I made mine based around that. I started drawing inflation and incest art then hoping you would find my work. As the years went by and you never watched my page, I almost lost hope.  

Then a few weeks ago you finally stumbled across my page. When I saw you were watching me, I nearly cried. I was so happy. It was what I had always wanted. Then as the bulge in your pants grew bigger and bigger, I knew I was the cause. I didn’t think I could cum so many times, but knowing you were getting so turned on by my artwork just made me so horny I couldn’t help myself. The reason I had to have my floor replaced wasn’t that I had a leak in the ceiling. It was because I played with myself for so long and came so many times, I flooded my bedroom floor and spoiled the floorboards. That’s how much knowing you were getting off to my artwork turned me on. 

So, no more wondering Steven I’m a freak just like you and I want you to come into my room right now and fuck my brains out! 

Steven shuddered as he read the last words, his cock and balls started growing again. “Ohhh fuck! I’m getting even bigger!” he shouted as his cock pulsed harder and harder, pushing out fatter and longer. “Unnnghhhh shit! I’ve never been this horny! It’s too much! Ahhhhh!” Steven cried out in pleasure as his cock pushed out past the six-foot mark and kept adding more inches. The growth had never lasted this long before. Was this it? Was this the straw that broke the camel's back?  

Bigger and bigger his erect penis swelled, getting harder and longer it blew past seven feet long and kept going. “Yes! Yes! Bigger! I want to be hornier! Yes! I don’t want it to stop!” But it did, and as his cock expanded past eight feet, it came to a halt and his cockhead erupted with a volcano of cum. Steven bellowed in ecstasy as he came and came. His cock throbbing with every shot. He painted his wall with his semen, covering it from ceiling to floor with thick wads of his viscous load. After what felt like an hour of cumming, he slid out of his chair thumping to the floor. There was another ding from Florence.   

InflatableIncestGal: That sounded so hot. Please big brother I need you in here now my pussy won’t stop overflowing I’m so horny. I need your cock! I need you inside me now!  

P.S. I have one more surprise for you, so hurry up. 

Steven summoned energy from his depths and stood up again. His cock was still throbbing away as hard as a bar. As he made his way to his sister's room, he could see liquid pouring out from under her door. Steven threw her door open and came face to face with the sight of his sister rubbing her pump pussy with both hands as she continued to gush and gush from her pussy. As her eyes fell on his cock, she started to spray even harder “holy shit I’ve never seen it hard before! It’s so fucking sexy looking! Ohhh god yes! It’s making me even hornier!” Florence shouted, spreading her legs wider as her pussy started to swell up. 

“Ahhhhh god! My pussy! What’s happening? Ahhhh it’s getting fatter and juicer! Ohhhh fuck! I’m getting even hornier! I’m cumming harder! Yes! Yes! Yes!” Florence screamed as her pussy expanded bigger and bigger and bigger between her legs. “Unnnghhh is this what it felt like for you Steve?” Florence cried out as she continued to rub her ballooning pussy with both hands. Her juices were spraying out so hard now they were covering Steven and the back wall in pussy juice.  

Steven, watching his sister go wild with lust, let out a groan of his own “fuck yes! Keep rubbing that fat pussy Florence. Don’t you dare stop getting hornier! Fuck I need to….” it was only then that Steven noticed that Florence had multiple hoses plugged into her nipples, belly button, and ass. “Uuumm sis, what are the hoses for?” He asked, licking his lips. 

Florence groaned “ohhh shit I forgot, seeing your massive cock just made me go crazy,” she lifted up a remote into view “it’s my surprise,” she added before pressing the on the button on the remote. A loud hissing filled the air and one after another Florence’s breasts, belly, and ass cheeks started to inflate bigger and bigger and bigger like balloons. Florence's assets rapidly swelled up, expanding out, filling up like basketballs, then beach balls, then quickly onto yoga balls. “AHHHHHH! This feels amazing! Why haven’t I done this before! Ohhh shit! Ohhhh shit! Ahhhh it’s making me hornier!” 

Steven looked between Florence’s legs and confirmed her pussy was blowing up much faster now. Her juices were pouring out like a raging river now flooding the floor, flooding the house. Steven felt his pulse start to pound harder than ever and he started to huff and gasp. He knew what was coming. Angling his cock down from across the room, he shoved the head of his cock into his sister's giant pussy. He heard her screech with pleasure as his massive cock head entered her. Her tits were already bigger than her computer desk. Her belly was just as massive. As he pushed his cock deeper inside Florence it started to grow again. Only this time it just kept going. 

Swelling past ten feet it grew out like a jack’s beanstalk. Florence’s belly was bulged out as his cock grew beyond fourteen feet. Steven’s hips pumped in and out thrusting more and more of his giant cock deeper inside of his sister’s expanding pussy. “AHHHH FUCK!” Florence yelled “IT’S STRETCHING ME SO MUCH! Keep growing, big brother! Grow! Grow! GROW!” Florence demanded “Unnnghhh fuck! Split me in half with that giant fucking cock!” she shouted practically drooling over how much she was being filled at that moment. Driven by her ever-growing lust, she picked up the remote to the air hoses that were inside of her. She pushed down on the plus button hard. The hissing grew louder and louder as the air pressure grew; Florence started to inflate much faster. She kept pushing down harder onto the remote until there was a crack. "Perfect," she cooed "now I can't ever stop," she said as she tossed the remote aside.  

Watching his sister blow up so massively in front of him only turned Steven on more and more. His cock throbbed and surged outgrowing and growing. As he thrust into his sister her cock-shaped belly bulge smashed through the walls of their house. “Ohhhh fuck! You’re making me too horny sis I can’t stop growing! Unnnghhhh! Fuck! It’s like your comic we’re just going to keep growing bigger and bigger forever!” Steven shouted in bliss. The two siblings moaned together as their expanding assets leveled more and more of their house.  

“Yes! Fuck me through the house! I can’t stop cumming! I love being so horny! I never want this to stop!” Florence ranted as her tits and belly burst the roof off their house. As the breeze blew across her swelling blimps, she could only squeal in delight. This was the best thing that had ever happened to her. She had been aching for this for so long and now that it was happening, she wasn’t going to stop. The two of them kept fucking and cumming harder and harder as they grew. It wasn’t long before Steven’s balls were each the size of a house. Still, it didn’t stop there. With every thrust, his balls only grew more and more, faster, and faster.  

When he finally came inside Florence, he blew her belly up and up and up until it was big enough to fill a football stadium. However, as he kept thrusting it became clear that his cum wasn’t ending it just kept pouring out filling his sister more and more. “I can feel every last drop pouring in! Ohhh fuck! Knowing I’m becoming my brother's cum balloon is so sexy! Pump me up with oceans of cum!” Florence exclaimed. Steven grabbed Florence’s legs and pulled her down to his base, hilting his cock all the way inside of his slutty sister. She wrapped her legs around his waist and shouted “I’m never getting off this cock. I’m going to fuck you till the end of time!” 

Hearing his sister’s lustful shouts drove Steven crazy with lust he loved that he just kept getting hornier and hornier there was no limit to how sex-crazy he could get. They kept fucking harder and harder making the ground shake as they grew and grew and grew. It wasn’t long before Florence’s ass cheeks were bigger than the city they had grown up in. Steven’s balls pushed out into the ocean as they expanded fatter and fuller with cum. All of which he dumped into his sisters’ mountainous belly. Her tits and belly continued to swell and swell pushing higher into the sky until it looked like three flesh-colored moons were connected to the earth.  

As Florence’s air-filled balloons swelled out into space, the lack of vacuum caused them to start to expand rapidly, faster, and faster and faster. Florence’s eyes rolled back into her head as she was subjected to more and more pleasure. Her ass cheeks and Steven’s balls engulfed the earth as they continued to force themselves to get hornier and hornier, neither of them wanting to stop. Steven’s cock was larger than the earth now. His balls made the earth look small. Still, he begged for bigger for a fatter, longer cock to fuck his sister even harder with. Florence cried for the same and for her tits, ass, and belly to keep inflating.  

“Ahhh I want us to grow bigger than everything now! I don’t care about anything else in this universe! I just want us to keep getting hornier and bigger! It’ll never be enough! Bigger! Bigger! Bigger!” Florence begged as her sexy solar system shattering blimps kept expanding faster and faster until they started to rival galaxies. Still, it continued with no signs of ending. The siblings lost in a sea of continuously growing lust, forever stronger orgasms and perpetually larger sexy bits couldn’t be happier. As Florence’s breasts, belly, and butt cheeks and Steven’s cock and balls expanded so large they made galaxies look like insignificant specks. The two of them only had one thought. More! 

The End.