Taeyeon is Tiffany's little cute sister, who was accidentally born with a male genitalia. Because of this their parents hide the poor Taeyeon from the world's full of hatred eyes. They never wanted people to hate their little daughter just because of what she is. From the start Taeyeon was not normal and her behavior seemed to be a boy's instead of a girl's. She always played with robots and cars, the opposite of her big sister Tiffany who was the epitome of girly, so their parents decided to hide the fact about their little daughter being a girl. Tiffany as a big sister always protected her little sister. When Taeyeon was bullied by other kids, Tiffany would protect her. Taeyeon grew fond of Tiffany and they became inseparable. Even though Tiffany is with two years older than her, they were from kindergarten until middle school in the same class. And now in high school the parents decided to put Taeyeon in the same class as Tiffany again, but this time Taeyeon became the one who protects her big sister.

Today was the second day of high school and Tiffany immediately made friends. She was lovely, bubbly and everyone liked her. Well who wouldn't love her? The teacher entered in class and placed her book on the desk.

"Good morning, class. My name is Mrs. Kim Yuna and I'll from now on, your math teacher. Since it's the second day, I'll let it be easy. Today we also have a new student." the teacher spoke. Tiffany smiled, knowing it was her little sister. The door opened and inside stepped a figure with short pepero hair, tied into a small ponytail, and wearing the male uniform of the school.

"Hello, my name is Erik Hwang. Please take care of me." Taeyeon's parents added another name for Taeyeon, which was a boy's name, hiding suspicions about her gender.

There were multiple squeals inside the classroom as some girls were fangirling over the new hottie. Tiffany chuckled seeing how the girls were basically going gay over her little sister, unknowingly of course. Jessica who was sitting at the same desk as Tiffany, and whom was her best friend, grinned.

"Ok, Mr. Hwang. You can sit beside-" Mrs. Kim couldn't finish as Jessica raised her hand, dragging all the attention at her.

"Yes, Ms?"

"Jessica Jung." she stood up and bowed."He can sit here." Jessica added. Taeyeon wasn't paying attention as she was practically staring at Tiffany, her elder sister.

"Ok then. Settle down and let's begin the introduction. I want everyone to speak a little about themselves." Taeyeon looked at Jessica and gave a shy smile. She then proceeded towards the desk. Once she was there, she put her bag down and sat on the chair. Because now her place was taken, she had to sit next to the school's nerd. Kwon Yuri, a tan shy girl with jet black hair and nerdy glasses.

"Hey." she sat down and waved. Yuri looked at the beautiful girl and blushed madly, not believing Jessica was sitting next to her.

"We're desk mates now." Jessica gave Yuri one of her sweet smile, making the latter blush further.

"Hey TaeTae" Tiffany eye smiled towards Taeyeon, who had a blank face on. Taeyeon was the silent type while Tiffany was all loud.

"Hey noona" Yup, Taeyeon already learned to call Tiffany noona, even though both were girls in some way or another. Tiffany accepted it of course. The class ended quickly and tons of girls gathered around the sister's desk.

"Hey Erik oppa." one of the girls spoke with aegyo. Of course none of them caught Taeyeon's attention. Only one girl did, and that was Tiffany Hwang, her elder sister. Everything Tiffany did was perfect in her eyes. Tiffany was perfect in every way. Taeyeon knew this was a sin, falling in love with your blood related, with a member of your family. She wasn't fond of the word incest itself. But she couldn't stop staring and thinking about her. They were always together and her love for Tiffany was growing each day.

"You girls should give Fany's brother a break." Jessica appeared beside Tiffany and smirked. The girls gasped and looked at the siblings.

"Omo! Tiffany, you have a brother?" Tiffany giggled at them before nodding.

"Fany-ah, I need to go to the toilet. Can you show me?" Tiffany eye smiled at her sister and nodded. Once they arrived at the boys' restroom, which was next the girls' one, Taeyeon disappeared inside. She couldn't hold it. She unzipped her pants and let out her annoying buddy out. Yes, she called it annoying because of him she couldn't live like a normal person. But sometimes she was happy with it. A boy came inside and took his smurf out of his pants. Seeing that, Taeyeon almost burst in laugher. The guy looked down and silently gasped at Taeyeon's length when it was soft.4 inches wasn't bad for a soft dick, while his was just 2 inches. However the guy was way taller, 6 ft tall and well-build, while Taeyeon was the same weight as her sister and thin. Of course she was working up, but the muscles weren't that showing in clothes.

Taeyeon grinned like a child and put her buddy inside before going to wash her hands, and leaving the guy dumbfounded at the shocking revelation he just witnessed.

Tiffany was waiting outside. And the rest of the day was the same. After three months every girl in school knew about Taeyeon and more than half had a crush on her. She was as always, uninterested, the time passed fast as it was already the end of the year. Unfortunately for her, Tiffany got a boyfriend, whom was the same guy she met in the restroom. His name was Choi Siwon, the school's most popular guy and the school's football team's captain. Aside from not having a dick at all, he was sweet to Tiffany and Tiffany was happy with him. Taeyeon couldn't put her finger on why Tiffany liked that guy. In her opinion he wasn't that handsome and having a smurf inside his pants wasn't the biggest advantage. Taeyeon rejected all the girls at school just because she only needs Tiffany. Taeyeon got friends, boys and she kind of guessed about what they're usually talking about. Porn, porn and more porn. Of course Taeyeon wasn't a pervert, but she needed to release herself somehow. She watched porn, and even used her hand. Her sister didn't know about this.

Today Taeyeon was with her group of boys when one of them named Henry, began talking about his hot elder sister.

"Henry, we know your sister is hot. Don't need to tell us again." another one, named Kris said. Henry rolled his eyes and told them about what he did. The others' mouths went agape and Taeyeon's eyes widened. She couldn't believe how perverted her friend is. Henry told them about how he stole his sister's worn panties while she was showering, and used them to jerk himself off. Taeyeon should've felt disgusted, but instead of that, she grew hot from inside. And her perverted self came out. They talked about other things until it came to Tiffany. They praised Taeyeon for having such a hot sister and how lucky she was to have her. They tried to ask Tiffany out, but they didn't have the courage to do it so in the end they gave up, knowing there was no chance for them.

Taeyeon rolled her eyes when she heard his name being spoken. And she unconsciously spilled out about his smurf.

"Oh, you're kidding me right" Joon laughed his ass off.

"2 inches I say." and they began bursting into a laugher.

"Anyway since we're talking about this. Have you guys measured it yet?" Henry grinned. The others stopped laughing and became serious.

"Soft or erect, man?" Aron asked.

"Both." Kris rolled his eyes.

"Erik, you tell us first." they smirked. Taeyeon looked at them before speaking.

"4 and 9 inches." there was a pause. No one said a word. They looked incredulously to Taeyeon, but she had that serious face on and when she looked serious then it must be true.

It's been a week since that discussion. Taeyeon kept thinking about Henry's perverted story. She didn't really believe it, but she didn't care anyway. Today was Saturday and Tiffany was out with her boyfriend, leaving Taeyeon by herself since their parents weren't home right at the moment. She was bored, but then the main door opened and inside came Tiffany with a smile on her face.

Both were in Tiffany's room.

"I'm going to shower-" Tiffany was cut off.

"Can we shower together, like when we were kids?" she looked into Taeyeon's puppy dog eyes and she couldn't bring herself to say no. Inside the bathroom, Taeyeon was sitting down, a towel in her lap and Tiffany was in her naked glory. The time passed and both grew up. Tiffany became sexier by each day and Taeyeon didn't remember if the last time they showered together, Tiffany's breasts were that big or not. Tiffany right now was washing Taeyeon's hair, her fingertips massaging her scalp. Taeyeon relaxed while Tiffany giggled.

"God, Fany-ah~" Taeyeon moaned, her hands gripping tight on her knees.

"Tae, you're just too cute to resist." Tiffany laughed and started to pour water on Taeyeon's hair. The younger girl stood up and placed her towel down. Tiffany's eyes wandered on her sister's body and realized that they're already grown up. They're not kids anymore. Her eyes stopped at Taeyeon's crotch and Tiffany swallowed her saliva. Taeyeon really grew up. After they finished washing, Taeyeon pleaded for Tiffany to sleep together. The elder sister accepted and right now both were in bed, with Taeyeon snuggling closer to Tiffany's warm and strawberry scented body. Tiffany kissed Taeyeon's forehead and smile before both fell asleep.

Hours later Tiffany stirred when she heard groaning. Sleepily, she turned to look at Taeyeon and the sight shocked her. Taeyeon was all sweaty, her eyes shut and her chest was heaving up and down. She seemed like she was having a nightmare or something. Her eyes went lower and saw the huge tent in her sister's shorts. Tiffany's eyes widened as she froze. She didn't know if she should wake Taeyeon up or not, but she did wake her up by slightly shaking her.

"TaeTae, wake up." Taeyeon's eyes shoot open as she sat up. Her face was burning red from the dream she just had. Looking lower she saw her erection inside the shorts, and then she looked at Tiffany and gasped softly.

They looked at each other. The moonlight was illuminating the room slightly through the curtains.

"What happened?" Tiffany knew it was the stupidest question ever. She should've realized that they're already teenagers and their hormones were already triggered. Taeyeon's was already triggered. If she was inside her room, and not Tiffany, she would've probably just waked up and began masturbating just to let the burden fall off her shoulders. Taeyeon looked away, embarrassed by everything.

"I-I have to go. I'm sorry." she stood up to leave, but Tiffany grabbed her wrist.

"And what are you going to do?" Tiffany's voice was soft and calm."Masturbate? Why didn't you tell me about this? We're sisters, remember? We're always here for each other. And I'm here for you." Taeyeon's eyes widened as she looked straight ahead.

"Would you let me help you?" Taeyeon thought this was some kind of dream. So she shook her head just to realize it was real. She looked at her elder sister and saw her serious face.

"Fany-ah, you don't have to. I don't think it's a good idea." Tiffany thought the same, but screw it. They were too fond of each other to care anymore.

"I-I know but we're always together. I can't let you suffer." Taeyeon sat down on bed beside her sister. Tiffany swallowed and reached for Taeyeon's shorts, slowly pulling them, revealing a pair of white Calvin Klein boxers with baby pink waistband.

"Do you often touch yourself?" Tiffany was curious and Taeyeon awkwardly rubbed her nape.

"A lot. I-I mean when it thinks by itself and I can't do anything." Taeyeon's voice came out as a whisper.

Tiffany smiled warmly and kneeled in front of Taeyeon, slowly pulling the boxers briefs off. Taeyeon felt vulnerable to be exposed like this and her sister gasped at her 9 inches erection. It was twitching at the sight of Tiffany.

"Mmm, it's cute." she touched the tip using her finger. Taeyeon blushed madly, her cheeks burning. She never ever thought about doing something like this with her sister. Tiffany rubbed its head between her index and forefinger, squeezing it slowly and some precum. Taeyeon's breath hitched before growing heavier. Nobody touched her before and having her lovely sister doing it seemed like a miracle.

"C-can you t-touch more?" Taeyeon pleaded and Tiffany finally wrapped her slender fingers around the shaft, its veins pulsating against her palm. Taeyeon sighed softly, leaning on the headboard and letting her sister do the job.

"It's so big, way bigger than Siwon's." Taeyeon gritted her teeth and suddenly yanked Tiffany's hand away.

"T-Tae, what's wrong?" Tiffany was startled by Taeyeon's suddenly change of mood.

"Always him, why do you always have to bring him up whenever we are together?" Tiffany was confused, her brows furrowed.

"What do you mean?"

"I hate him. I hate it when you're talking about him. I hate it when you go out with him instead of staying home with me. You forget about me and rarely talk with me. How do you think I feel? I feel like shit, because I love you so much it hurts." tears were threatening to fall from her eyes but Taeyeon bit her lip, suppressing them from falling.

Tiffany was speechless.

"It's so fucking wrong to fall in love with you, but I did it anyways. Good night!" Taeyeon picked her shorts and was ready to leave when Tiffany spoke.

"If I-I break up with him, you'll be happy?" Taeyeon's eyes widened as she suddenly turned towards Tiffany, whose head was lowered down.

"Yes..." she responded.

"I can't lose you 're my everything." Tiffany sobbed, making Taeyeon run towards her and pulling her into a hug. Taeyeon's arms were securely wrapped around her elder sister's body.

"Fany, love you so much." they pulled away and looked in each others' eyes. Taeyeon swallowed before gently caressing Tiffany's cheek and wiped the tears away. She closed the proximity between their faces as she leaned in. Tiffany closed her eyes when she felt Taeyeon's lips on hers. Her hand reached down and pulled Taeyeon's boxer briefs off, throwing them away. They soon parted away to catch their breath. Both were blushing hard. They just kissed. Taeyeon felt Tiffany's strawberry lip balm taste on her lips. The taste was addicting and her elder sister's scent was intoxicating.

Tiffany got a hold of Taeyeon's erection, slowly pumping her hand on its length. Taeyeon shut her eyes and the pleasure take control of her body. She smiled and felt something soft and warm on the head. When she opened her eyes she found Tiffany's mouth peppering kisses all over the erection, before finally engulfing it. She slightly sucked on the sensitive head, her tongue circling the tip and running over the small slit. Taeyeon gripped the bed sheets, as she never had a blowjob in her whole life. She saw in porn, but never experienced one and Tiffany seemed to know what she was doing. Taeyeon bit her lip and fisted Tiffany's hair onto a ponytail.

"Oh fuck!" and she came right into Tiffany's warm mouth. The semen was squirting down Tiffany's throat, as she swallowed all of it, milking Taeyeon to the last drop.

"F-Fany," Taeyeon panted and lied backwards. Tiffany wiped her mouth and proceeded to take off her shorts and tank top, remaining in all her naked glory in front of Taeyeon's lustful eyes. They knew both were virgin. Tiffany straddled Taeyeon's hips and gently positioned the erection in front of her core. Her outer lips were burning and coating the tip with her precum. It was slick and leaking.

"Wet, you're so wet, Fany-ah." Taeyeon thrusted her hips, slowly, forward and Tiffany winced in pain, falling on top of Taeyeon.

"Fany, are you ok?" Tiffany could barely move her body. She felt herself going numb.

"Y-Yes." hearing the signal, Taeyeon flipped Tiffany over, holding onto her thighs.

"I'm going to move, ok?" Taeyeon kissed her sister's forehead and started to move her hips slowly. Blood was oozing from Tiffany's core onto the bed but neither cared.

The unbearable pain slowly transformed in pure pleasure as Taeyeon fastened her pace, thrusting with speed inside her elder sister. Tiffany wrapped her arms around her little sister's torso, her nails trailing over the soft skin, leaving behind red marks.

Taeyeon groaned and gave one last thrust before cumming, the slick hot liquid filling Tiffany's womb. There was a pause for both to catch their breath. Tiffany began bucking her hips and Taeyeon went hard again, still inside her.

"G-God, T-Tae," Tiffany moaned and hid her face onto the crook of Taeyeon's neck. Her breath became irregular and her body convulsed. She came hard, her juices squiring over the bed. Taeyeon was still thrusting, hard. The head of her cock hitting Tiffany's g-spot repeatedly. Tiffany's warm walls were fully engulfing her whole being.

"F-Fany, I'm gonna-ugh"

"Me too. Come inside, please come inside, TaeTae." and with one last thrust, both came. Tiffany wrapped her legs around Taeyeon's waist making her stay still while she was filled once again. With ragged breath, Taeyeon pulled out and white semen was slowly dripping from Tiffany's now sore hole. Taeyeon leaned in between her sister's legs and ran her tongue over the outer pussy lips, tasting the mixture of both of them and a little blood.

"Tae," Tiffany pulled her up and kissed Taeyeon passionately, tasting the same mixture. That night was just the beginning. Their actions were bold towards each other. Tiffany broke up with Siwon just as she promised, but the guy didn't accepted it that easily until Taeyeon posted a photo of his smurf on the private student's site. Everyone was laughing at him.

Their hormones were always ragging and they would always find a nice place for a quickie, be it at school or in other public places.

Today Taeyeon was horny as hell after they had anatomy. Tiffany grabbed her arm and went behind the building, where there was a small warehouse where are the gym locked the door and Tiffany was already kneeling and unzipping her sister's pants.

"Fuck, I waited so much." Taeyeon moaned as Tiffany fully engulfed her, sucking hard and making slurping sounds. It was a sight to die for and Taeyeon felt herself lucky. Tiffany pulled away, her hand now finding the neglected balls and played with them in her hands.

"Shit!" Taeyeon pulled her shirt up a little and grabbed onto Tiffany's head and pushed her further, deep throat. Tiffany gagged and grabbed onto Taeyeon's buttocks, digging her nails into the soft flesh. Taeyeon came, her cum swallowed by Tiffany.

Taeyeon pulled her sister up and bended her over the vault horse bench. Tiffany blushed furiously as she turned and saw everything. Taeyeon pulled Tiffany's panties to her ankles and lifted her skirt up a little. She smirked and gently palmed both of her butt cheeks. With her free hand she was rubbing her cock.

"I want your beautiful pussy." and with that, Taeyeon plugged her whole 9 inches cock into Tiffany, making her legs go weak.

"T-Tae," Tiffany moaned as she was pounded from behind. Taeyeon smirked and grabbed a fistful of Tiffany's hair, jerking her head backwards. Tiffany let out a yelp of pleasure.

"Your. Pussy. Is. Mine. Mine. Only" Taeyeon banged hard at every emphasized word. Pulling out before suddenly thrusting, making Tiffany feel it in the pit of her stomach. Her eyes rolled at the back of her head and her legs were shaking furiously. Taeyeon gave one last thrust and Tiffany came, making Taeyeon explode inside her and fill Tiffany's womb with her slick warm liquid.

They didn't really care about protecting themselves or something. Taeyeon wasn't going to use a condom and Tiffany would never take pills. They thought there was no fun if they do that, and Tiffany preferred Taeyeon completely naked without some stupid plastic thing.

It was one week holiday and they're in train going to visit their grandparents.

Inside the compartment there was only the two of them. Taeyeon was sitting near the window with her headphones on, and listening to music. She didn't observe Tiffany's hand slowly unzipping her pants. She was too immersed in bobbing her head to the rhythm. Tiffany smirked and took out Taeyeon's soft cock. She placed it inside her mouth and began sucking it deliciously. Taeyeon opened her eyes and saw Tiffany. She smirked and took her headphones off. She placed her hand on her elder sister's back and threw her head backwards. Tiffany felt Taeyeon getting harder inside her mouth and she couldn't have been happier. She sucked on its head, twirling her tongue around the sensitive skin and over the small slit. Taeyeon's mouth was slightly ajar and her hands pushed Tiffany to take it all of it and deep throat her.

"Christ! I love your mouth, Fany." Taeyeon sighed and stood up. She told Tiffany to kneel on the seat with her back facing Taeyeon.

"I'm going to fuck you here, hard. Try to keep it shut" and without even waiting for Tiffany's response, Taeyeon was already inside her. Tiffany bit her lip as Taeyeon was pounding her hard. The door of the compartment was opened and someone could enter and catch them anytime. It was so wrong, but amazingly arousing.

"T-Tae-ahh, fuck!" Tiffany couldn't hold her moans any longer. Taeyeon's cock was hitting her g-spot mercilessly.

"T-Tif-fany," Taeyeon sighed, her balls tightening. Suddenly, there was a knock at the door and both were startled.

"Is everything alright there?" it was a check man, the one who checked their tickets. Taeyeon smirked evilly and put her hand over Tiffany's mouth, before fucking her behind harder. Tiffany's eyes widened as tears were brimming up.

"Yes, everything's alright here." Taeyeon responded and the check man left. With one last deep thrust Taeyeon came hard, exploding inside of Tiffany. Some semen was dripping from her sore hole. Taeyeon pulled out before burring her face in Tiffany's cunt, licking everything clean and bringing her elder sister to another mind-blowing orgasm.

This experience was amazing for both of them. However when they were at their grandparents, they couldn't have any sexual intercourse. The only thing they could do was foreplay, like oral sex, hand jobs and fingering. That was for only a week because they had to return home.

It was a sunny afternoon when they were inside the subway, returning from school. Taeyeon was suddenly feeling very horny and the thought of fucking Tiffany here in the subway and there were some people. The feeling of being watched in and having sex -which was very likely forbidden in a public place- was making Taeyeon hard and horny as hell. She nudged Tiffany, who was listening music, and made her turn. Taking her earphones off, Tiffany looked at Taeyeon, who was smirking and pointing at her crotch. Looking in that way, Tiffany saw the big bulge inside Taeyeon's pants. Taeyeon leaned forward and whispered in a sexy husky voice.

"I want to fuck your little pussy here inside this subway while everyone is watching." Tiffany shut her eyes and swallowed hard. Her thighs were rubbing against each other, trying to make the throb in her sex disappear. Taeyeon smirked and looked around before grabbing Tiffany's hand and placing it on her bulge.

"Suck me here." Taeyeon unzipped her pants and freed her already hard cock. Tiffany was flushed and her body was shaking with arousal. She leaned and wrapped her mouth around its throbbing head, making Taeyeon sigh in pleasure. She began bobbing her head fast, the head of Taeyeon's cock hitting the back of her throat.

"Yess, fuck. Suck me, suck my cock." Taeyeon held Tiffany's head in place and started moving her hips, and fucking her sister's mouth like an animal.

"Y-ye-ahh," that was the last thrust before her semen was already flowing inside Tiffany's mouth, some even dripping from the corner of her mouth.

That was the most arousing thing that happened to Tiffany. But Taeyeon wanted more, and more. She wouldn't stop. She wanted to fuck her elder sister in the most public places. And that's why when their mother sends them to buy some groceries, Taeyeon thought it was the perfect place.

Tiffany was tip-toeing to reach for a bag of chips when Taeyeon came from behind her and began rubbing herself against her butt. Tiffany blushed and threw the chips in the trolley.

"Let me fuck you." Taeyeon pleaded, like a kid who wanted a candy, but it was much more. There were people inside the market. The chance of being seen it's big. Without waiting for Tiffany's permission, Taeyeon lifted her skirt up a little and began rubbing her finger on Tiffany's sex, making her cry in pleasure.

Taeyeon stopped and whispered on Tiffany's ear."Be silent or someone is going to hear or see us."

Tiffany bit her lip as Taeyeon unzipped her pants and rammed her whole length inside her sister's pussy. Tiffany released her bottom lip with a sigh and Taeyeon's thrusts became incredibly fast and deep. She wanted to moan out loud, but the presence of people here was stopping her from doing so.

"Just. a. little. more-ahh" Taeyeon sighed with her eyes shut and a bright smile, as she released her load inside Tiffany, whose legs were slightly shaking.

"Fany, you're awesome." she gently kissed Tiffany's hair. That day they reached the extreme, and Taeyeon was never more proud of herself.