Charly is a tall 15 year old male tiger. He is currently living alone with his twin brother, sharing an apartment with the money their parents left them, after a terrible accident had taken them away from the two brothers. Both brothers shared almost the same appearance. Both having the same orange and white hair and fur color, also sharing almost the same stripes as the other, even their eyes were the same shade of baby blue. Making them appear as if they were identical twins up until puberty. But after they reached that age, their bodys both started to drift apart as their physical appearances shifted to different extremes. Sam grew into a handsome male Tiger with firm muscles even without working out and even adding an appropriate package between his legs, which he flaunted around whenever the chance arose. Charly on the other hand became more feminine,no matter how hard he tried working out, the only thing growing more sizable on his body were his ass and thighs, much to the young tigers dismay.
The first time Charly knew just how much things between him and his brother would change, was when he caught his brother staring at his ass, even having a very noticeably erect penis shaped bulge in his pants. When Sam noticed his brothers awkward look at him, he knew he was caught staring, his lustful stare turned to anger as he covered his crotch and started to mock and yelling at Charly, pointing out how girly he looked and that he wasn't even half the man he was, being so pathetic, that he would dare and try to turn his own brother gay. 
Being met by such terrible words by his own brother, made him break down sobbing on the spot. He was hoping that this kind of thing wouldn't repeat itself, but he couldn't have been more wrong. For most of their life together up until now, his own brother would become his biggest bully, being scared to come back home. Until that day school was already hard enough as it was, with all the guys teasing or bullying him for his girlish appearence. Now his brother had joined them, even giving them more details to make fun of him then before, like his small dick. Before he could also escape everything once he got home, but now he couldn't as his brother was there waiting for him and it was just getting worse each day.
They were 14 when their parents had that terrible accident, leaving them living alone in a small apartment. For Sam it was almost it blessing it seemed, as with their parents out of the way, there was no one to stop him, so the bullying became even worse as his brother made him dress in girl clothes, even throwing away his old ones, making the bullying at school hell, as he was forced to go outside in a pink skirt and Sam would make sure Charly would have to leave the house as often as possible. 
His brother even started to humiliate him even more especially because of his tiny cock, which was just as small as it has been before he hit puberty. Sam would often force the bathroom door open when Charly was taking a shower just to laugh at him, even taking pictures. The only thing giving Charly strength at this trying time was, that he could often and clearly see that his brother was getting aroused by his body, even catching him masturbating to the pictures Sam had previously taken. So Charly quickly figured out Sam was gay, way before anyone else knew about it, hoping that when Sam's secret sexuality would finally come out, he could turn the tables on his brother and make him pay for his suffering. But what he didn't figure out was, just how much Sam desired him and his, thinking he was just attractive to men in general, being sure Sam would never consider incest as an option.


So one day after he came back from school, dressed in his girl clothes as always, he was taken by surprise, when the door suddenly slammed shut behind him. When he turned around, he was worried and scared to find his brother standing there, quickly locking the door with a devilish grin on his face. Only after a long moment did Charly notice the truly terrifying thing in this situation. His twin brother was standing there fully exposing his naked body. Charly had gotten used to seeing him naked around the apartment, as Sam had made it a point to show off his "superior" cock to his brother all the time. But it was very different this time, because now Sam's big member was hard and throbbing, being covered by his own pre cum, which was running down from the tip of his cock.
Charly rapidly and hastily backed off instinctively, causing him to accidentally trip and fall on his bed, making his brother laugh in response.
"Oh you are so willing you are already laying on your bed?!" 
Sam said in a sneering tone, making Charly even more scared of the situation on hand, as he was quickly putting everything together, figuring out his brother's perverted intention.
"But I am not gay you psycho, you don't want to do this, please stop."
Charly's pathetic attempt at begging, only made Sam snicker and his cock throb in response. Sam was so excited his cock was shooting pre on the floor as he moved dangerously close towards Charly, all while he slowly stroked his massive cock with one hand, which didn't even fit all the way around the thick shaft.
"Oh but I do want to do this, very badly in fact, and you know its not gay considering how much of a girl you really are, even being dressed as one, like a fucking faggot!"
Charly quickly tried to cover himself with his blanket, but to his horror his brother was already too close, pulling the sheets away from him with one hand, while lifting up Charly's skirt with the other. beneath it were the pantys he just baught a few days ago, which even made Charly's small girl cock form a small bulge, clearly showing how small he truly was.
"Please don't do this, we are brothers, it's not okay! I will call the police!"
Charly cried out, beginning to sob, as he was made to feel even more powerless, being pinned down by his brother so easily. He was even unable to try and fight it, just laying there, letting it happen.
"Go ahead little bro, call them! But know that if you do, everyone will find out that you got fucked in the ass by your brother, one way or another. And guess who they're gonna believe more at school, when I tell them that you actually begged me to do it with you?!"
Charly choked, being called little brother was a first and so wrong they were twins and in fact he was the one who came out first. But right now he surely felt like one, as all he was able to do was sob and try to beg his twin brother to stop and even that became harder with every passing moment, as his voice began to fail him, only letting out squeaks, making him almost sound like a mouse in distress.
Forcefully Sam began to tear off his brother's panties, forgetting that he had to purchase new ones, if he wanted him to wear them again. As the fabric Tore open, Charly's small cock and balls were revealed from underneath. Sam decided to not remove the skirt, to keep up an even more feminine appearance, for what was about to happen. Even though he hated the thought of being called gay for doing this, he couldn't stop himself, trying to humiliate his brother once more. So Sam knelt on top of Charly, placing his own cock on top of his brother's, showing just how big the difference in size and girth between their dicks truly was. Having his brother's huge cock so close, made Charly gasp out loud, accidentally breathing in his brother's musk, which was coming straight from that massive beast.


"Just look at how much bigger my dick is than yours! Go ahead, just look at how tiny yours looks, when you compare it to a true cock like mine-"
Suddenly, for just a moment, Sam stopped himself from insulting his brother further. Sam had felt a weird sensation, he wasn't prepared for, coming from his cock grinding against his brothers. He leaned down curious to what had caused it and when he looked more closely, he was met with a gut feeling that his wonderful cock was bigger just a moment ago. But he knew better than to concern himself with the impossible. To spite his brother more and because it felt amazing, he slowly started to grind his big cock against his brother's limp pathetic girl dick. While doing so, the same incredible feeling from before washed over him once more, forcing him to moan out of pure pleasure. This time not even bothering to look down, thinking he was just paranoid and besides he was enjoying that fantastic feeling way too much.
Charly on the other hand was very intently staring at both their dicks rubbing against each other, foreskin being pulled back and forth and precum leaking and smearing between them. But that wasn't what caught his attention, he was much more interested in what else was happening, as he had noticed something else, something his brother thought was only paranoia and it was making Charly incredibly hard and excited. While he was feeling a similar sensation to the one his brother was experiencing, he noticed that every time he felt it, his cock would grow a tiny bit, while his brothers would shrink by the same amount he gained. He didn't know why this was happening, barely able to cling to reality in this situation, scared it could just be a dream. But it was happening, maybe it was a hidden ability of his, but what he knew was, the more he got excited and the more he wanted to grow, the quicker the process became. 
During this ordeal Charly's and his brother's cock were leaking and shooting thick pre cum like crazy, especially as each Sam's would shrink while Charly's grew more. All the cream between their cocks was making everything more pleasurable, acting as a kind of lubrication. Eventually however, when his brother Sam was so lost in pleasure, that he moved his hands down to stroke their meat sticks together, not caring about being gay for a moment. But when he felt their dicks inside his hand, he let out a sudden and shrill shriek of fear when he felt them to be about the same size by now, realizing his naging fears he had pushed aside, just became reality.
Startled from the unexpected sensation Sam backed off hurriedly, falling backwards on the ground, staring in shock at his shrunken cock and at his brother's now equal sized fucktool. Charly didn't miss a beat, as he saw his chance for revenge. His cock was throbbing and hard, while he was eager to make his cock grow even more, taking it away from his bully of a brother. So he quickly pounced on top of Sam, to continue grinding their fuckrods together, pinning down his brother. Sam had begun to take on a more feminine frame with every bit of cocksize that was robbed from him, leaving him with a lack of strength to defend against Charly, as even more was now quickling being taken away. 
Eventually Charly reached the same size as his brother's cock once was. The thought of stopping himself now crossed his mind, this outcome seeming fair to him at first. But as he remembered all the pain and suffering his brother inflicted onto him, with his constant bullying and lust slowly clouding his mind he knew it wasn't enough punishment. So he continued frotting his brother, who to his surprise suddenly started to cry and beg him to stop. He had never seen his brother in a state like this, but he wasn't stopping now, Sam didnt listen when he begged him to stop, so he wouldn't either. As Sam began to lose the last inches of cockflesh, his disappearing balls began to form into a virgin cunt, while his dick would shrink further to form his clit. 
His, or as it was more appropriate now, her voice had changed as well, now sounding like the girl she became. All her previously maskuline features disappeared, her muscles weakened, while only having gained C-Cup tits and a thicc ass like her brothers. While Sam was drowning in despair, Charly felt a new kind of power, as his cock had become even bigger than his brother's ever was, even with big round balls to go with it. And now Charly even had something he actually wanted to fuck right in front of him, his brothers or now sisters virgin pussy was ripe for the taking.


Sam was still in shock, barely able to cope with all the sudden new changes to her body. She was unable to stop her sobbing, as she saw her brother's massive cock, most of which was once hers. She knew she was pathetic laying there, only able to cry and not do something about it, while only begging her brother to stop and give her dick back. She was so caught up in her despair, that she didn't notice it at first, when her brother stopped grinding his cock against her pussy. Only when the sudden pain from losing her virginity shot through her body, she looked down, horror washing over her face once more, as she saw and felt how her brother's huge tool entered her new pussy and defiled her with its massive size. She wanted to scream and somehow punish her brother, but then she slowly realized the irony of the situation. As only their roles had swapped, having had plans to also rape her brother like he was doing to her now. Only having been stopped by a cruel or maybe deserved change of fate.
Realizing that, made her slowly calm down and relax and give into her fate as her brother's new fucktoy. If she just would have been a better person this would have never happened in the first place, but she did what she did and so she deserved to be punished, not being made to feel like one, but actually made into a girl. Charly on the other hand didn't care much for his sister's sudden change of heart, as the only thing he noticed was that her pathetic crying stopped and her entrance finally got loose enough for him to push his monster all the way inside his sister. His large cock was reaching just far enough to push against her cervix with every thrust, but still being large and thick enough for him to see the outline of his cock on her belly. He felt like he was in heaven, his sister's new pussy was just perfect for his now enormous cock, like this was always meant to be.
So now that he could finally comfortably fit his fuckrod inside her tunnel and press against her fertile womb, he began thrusting into his sister. At first his thrusts were slow and careful, concerned he would slip out and she could get away from him. But as time passed, he got more confident and bolder with his movements, making big and hard thrusts against her cervix, almost as if he was trying to break down a door in its way. Sam had begun to moan out loudly with each of his thrust, her body begging her for more and her mind getting fuzzy. His hands moved up on her chest to grope and massage her firm and perky tits, only now realizing how much he longed for a woman's body around his cock and now he had one right underneath him. If he remembered that, his now sister was sharing the same apartment as him and that he was in control now, he maybe would have taken things more slowly, savoring the moment. But right now he only wanted to ruin her pussy, fucking his sister like there was no tomorrow, making sure she wouldn't be able to walk away. By this time the air was heavy with the scent of sex and sound of their bodys colliding and the moans of Sam.
All throughout this fucksession Sam started to cope more and more with the situation, even beginning to enjoy, no she loved, being fucked like a toy for her brother. Eventually she even started to moan Charly's name, thinking that maybe this was what she was meant to be, not the alpha male she thought she was, but a female fucktoy for her brother she was right now. When she felt Charly getting close, as his cock throbbed so hard she felt like her body was shaking, she hugged him tightly, wrapping her legs and arms tightly around him. She was making sure his cock would stay right where it was, filling his seed directly into her womb. Her body wanted to get pregnant, no she wanted to get pregnant with his child…


A couple years after that first fateful night together, when they both turned 18 they already had three children with more on their way, two boys and one girl, though they knew it wouldn't stay that way for long.