My Older Sister (Short-haired Huge Breasted Girl In The Basketball Club) Who Is Three Years Older Than Me, Said For My Birthday, "I'll Become Your Sex Slave," And Actually Let Me Have Sex And Cum Inside, But Her Love Is A Little Heavy - Chapter 1
On a humid summer night, I was getting ready to go to bed and considering what masturbation material to use, when I heard a hesitant knock at my door. When I opened the door, my sister was standing there, her cheeks flushed.
“Eh, what’s the matter, this late?”
“Well, it’s because tomorrow is your birthday.”
“Ah, it’s my birthday, huh? Wait, are you giving me a present?”
It’s unusual for my sister to give me a gift. Riko, my older sister who is three years older than me, is a university basketball player. She’s a beautiful girl, 175 cm tall, with large br3asts that seems a bit impractical for basketball. She nervously brushes her short hair back.
“A gift from you, sis? That’s such a surprise! What kind of present did you get me?”
“…I.”
“Huh? What did you say?”
“…I’m.”
Unlike her usual clear and crisp way of speaking, my sister was talking at a very quiet volume, making it hard to hear.
“Huh? I can’t hear you well. Come inside, let’s talk.”
I invited my sister into the room. I thought she would sit on the bed, but instead, she sat in seiza on the carpet.
“I’m telling you that I’ll become your s3x slave. Even though it’s embarrassing, I’m gathering the courage to answer, so please listen properly.”
She’s making complaints about my hearing, but the first part of her words doesn’t fit with her attitude.
“…Huh? Did you just say ‘s3x slave’?”
“Yes, that’s right. You put ‘s3x slave’ written on your wishlist on your profile, right? If girls see that, they’ll hate you and you’ll never get a girlfriend. So I’m saying I’ll become your slave and fulfill your desires.”
My sister spoke quickly, her face bright red. Wondering if what she said was true, I opened my phone and went to check my profile.
“Oh, it’s true… My fetishes are completely exposed.”
“Exactly, if someone sees this, it’ll be a disaster. Delete it quickly. Sis will wait for you.”
It’s definitely something that would be bad if seen by others. But I don’t remember writing ‘s3x slave.’ For now, I decided to fix my SNS profile.
“…Huh? Why did I write ‘s3x slave’?”
“You’re the one that should know! Anyway, you can use my body as you like. But remember it’s your birthday present, so it’s only for today. Hurry up and give me orders, do naughty things, and release your perverted sexual desires.”
I thought it was a joke, but it seems like she’s serious. She’s blushing all the way to her ears and avoiding eye contact with me.
“Also, I’ve prepared the morning-after pill as well.”
“What do you mean by the morning-after pill?”
“Ugh, don’t make me say such things! I’ve properly prepared birth control, so you can just stick your d1ck in without worrying and have creampie s3x whenever you want. Come on, give me your orders already!”
I gulp nervously and then take another look at my sister’s body. With her large br3asts and muscular physique, my sister, who is taller than me, I wonder if it’s really okay to violate her.
“Well, then first take off your top and show me your b00bs… no, just show them, Riko.”
I nervously gave the command, but my sister lowered herself on three fingers and bowed in acknowledgment.
“Okay, Master. Please, cast your gaze upon my b00bs.”
When my sister slowly took off her top, she wasn’t wearing a bra underneath. Immediately, her large br3asts spilled out. They seem so much bigger than when she was wearing her uniform and playing basketball. I wonder when the last time I saw my sister’s bare br3asts was… Probably when she was in first year of junior high school.
“Wow, they’re really big. What cup size are you?”
“I have an F cup. These are the br3asts you’ve always been sneaking peeks at from the side of my shirt to see if you can spot my n1pples. Today, you can look as much as you want, so make sure to burn it into your memory.”
“Hey, can I take a picture?”
“Huh, a picture?”
It seems like my sister was caught off guard by the unexpected request. But after thinking for a moment, she nodded as if resigned.
“I was the one who said I’d become your s3x slave, so I’ll follow your orders. But don’t show my face, and don’t send it to your friends. If you’re going to use it for masturbation, you can take the picture.”
“Yay! Thanks, sis. I love you, sis.”
“Ugh, don’t throw away your first ‘I love you’ by saying it here…”
I took several pictures of her br3asts with my smartphone. As I enjoyed her pink, erotic n1pples, and the cleavage that she pushed together with both hands, I started to feel like seeing her pvssy next.
“Undress, Riko. Take your pvssy out and spread it with your fingers for me to see.”
“Y-yes, I understand.”
My sister stood up and pulled down her pajama pants. She was wearing proper underwear—a bright red, provocative one, just for me to see.
“Oh, wait, don’t take that off yet. You put it on for me to see, right? In that case, just shift your panties to the side and let me see your pvssy.”
My sister, embarrassed, opened up and showed me pvssy. It was well-groomed, and I could see her beautiful pvssy slit.
“Hey, it’s enough already. Hurry up and give me an order, Master.”
“Not yet. I can’t give you an order until I properly see your pvssy. Hmm… masturbate and touch your tits, get it nice and wet so that I can fvck you right away.
“Pervert… How lucky I am to have a brother like you.”
While complaining, my sister spread her legs from a sitting position and began to masturbate as instructed.
“Ugh♡ Mmm, haah, fuh… Being watched by you while I masturbate is so embarrassing.”
“But it feels good, doesn’t it? Hey, masturbate while looking into my eyes.”
“Okay, I get it. Ah, are you taking pictures even now…? You have to make sure my face isn’t in them, okay?”
I find my eyes fixated on my sister’s pvssy while I keep taking photos of her masturbating on my phone. The way her fingers move while touching her cl!toris and pvssy is incredibly lewd, and every time the love juice drips, her expression becomes more and more alluring.
“You’re beautiful, Riko.”
“I already know that without you telling me.”
“Hey, isn’t it strange to call me ‘you’ instead of ‘Master’? If you have trouble calling me ‘Master,’ then just call me Masaki. Now, tell me how it feels when you masturbate.”
“…Yes, being watched by Masaki, my pvssy is starting to feel really good.”
I wonder how many years it’s been since my sister called me by my name. When we’re on a first-name basis, it feels a little like we’re a couple, and it makes my heart race. Maybe my sister is getting excited being looked at by me, as the wet sound of her masturbation intensifies, and her breathing becomes more erratic.
“Ah, I’m about to cum. Masaki, I don’t know if I can hold back… Is it okay if I cum?”
“Yeah, go ahead and cum. Now, what do you do when you’re about to cum?”
“Ah… I’m a s3x slave, but I’m going to climax before Masaki!”
She tightened her muscles and arched her back, causing her body to tremble and convulse. It seems like she reached her orgasm. This is the first time in my life I’ve witnessed a woman masturbate until she orgasmed like this in front of me.
“Ah… ha…”
Even while my sister was orgasming, I kept recording her masturbating. Since it’s a video, it looks like it’ll be a great masturbation material. I quickly gave the next order to enjoy my sister.
“Hey Riko, put my d1ck in your mouth. I haven’t gone to the bathroom since I took a bath, so it’s clean.”
“… okay.”
My sister obediently responded and then pulled my pants down while I was sitting on the bed. Already erect from excitement, my d1ck appeared right in front of my sister.
“This is Masaki’s… Wow, it’s so big, I can’t believe it…”
“Quick, put it in your mouth. Just being watched isn’t enough for my d1ck to be satisfied.”
“Y-Yes… I’ll put it in my mouth… Mmm…♡”
My sister kissed the tip, then slowly took my p3nis into her mouth. Perhaps because it was her first time, she seemed a little uncomfortable. But soon, she got used to it and started moving her head back and forth.
“Ah, it feels so good… Riko’s mouth is so warm. Can you go deeper?”
“Mmm… L-Like this?”
My sister swallows my c0ck all the way to the base. I can feel her throat tightening. It seems painful, and she’s getting teary-eyed.
“Yeah, that’s good… Riko’s mouth pvssy feels really good.”
“Nnngh, mmph…”
My sister takes it all the way to the back of her mouth and repeats the motion of moving her head back and forth. Even though it’s just that, it feels much better than masturbating myself, and the thought that she’s serving me makes me excited. While petting my sister’s head, I grab her head to prevent her from pulling away, and I shove d1ck deep down her throat.
“Mmph! Mmmh!”
“Ahh, it feels good… You even let me deep throat you, you’re the best, sis. I’m going to cum like this.”
“Hmm? Mmph… Hmm!”
Without getting my sister’s permission, I ejaculate into her mouth, spurting my semen out. The first ejaculation not involving masturbation felt so good that I almost collapsed. As expected, even my sister seemed stunned by my ejaculation and some of my semen started leaking from the side of her mouth.
“Ngh… cough, cough. If you’re going to finish, at least give me more time to prepare… Ugh, my mouth is so sticky with your semen… I haven’t even had a kiss from Masaki yet…”
My sister spits the accumulated semen into a tissue while her eyes fill with tears muttering complaints. I actually wanted to order her to drink it, but the mood isn’t right.
“I’m going to rinse my mouth, just wait a moment.”
“Okay…”
After my sister leaves the room, I look at the photos I took with my smartphone. I made sure her face is hidden, but the photo of my sister with my p3nis in her mouth is really hot and cute. Just looking at it, my d1ck starts to revive.
“Sorry to keep you waiting… Wait, is your p3nis getting hard again?”
“Yeah. It’s because you’re cute, sis.”
“C-Cute…? I’m your s3x slave, so things like being cute don’t matter, right? Shouldn’t you just insert it into my pvssy and have s3x? I’m already wet and dripping because of your masturbation orders, so if you want to, it’s fine.”
As soon as my sister lies on the bed, she opens her arms, beckoning me.
“Hey, Riko, are you still a virgin? Or have you been with someone before?”
“No, I haven’t. But since I play basketball, I might not have a hymen anymore. Most of the girls on the team were like that too… So there might not be any bl00d, but I’m offering you my virginity, so make sure to be grateful and have s3x with me, okay?”
“The way you’re speaking. That’s not how a s3x slave should talk to their master. Plus, you’re using ‘you’ again.”
I leaned over my sister and whispered while gently nibbling on her earlobe.
“Make sure to beg me properly, Riko. Say clearly that you want to give your virginity to my p3nis.”
My sister, with her ears turning red, grabs my d1ck and slowly moves her hand up and down while saying her begging words.
“Please, insert your p3nis into my virgin pvssy, Masaki. As proof that I’m Masaki’s s3x slave, please thrust your p3nis in and cum inside me… Also, we haven’t kissed yet, so please. It’s still my first kiss. My mouth has experienced a blowjob before it’s first kiss, but please kiss me before inserting it.”
My sister asks her request with her ears flushed bright red. To be asked in such a lewd way, I really feel blessed.
“Riko, that was incredibly sexy. I’ll fulfill your request, but I’ll kiss you later. First, I’ll put my p3nis into your pvssy.”
“Eh? Ah, thank you so much…”
“First, let’s do it in the missionary position. Come on, spread your legs.”
I position myself in the missionary position and place my p3nis against my sister’s pvssy. Her face turns red as she opens her legs to receive me.
“Mmm… your p3nis is pressing against my pvssy. Hurry up and put it in…”
“No need to rush. I’m allowing Riko’s pvssy to get used to my c0ck.”
I can feel my glans going in and out of my sister’s pvssy opening. I slowly push my hips forward. Then, I feel my p3nis being swallowed up. It’s a bit tight since it’s her first time, but because there’s no hymen, it able to smoothly slide in deeper.
“Ah, ah… it’s coming in… it feels so strange. I’m really losing my virginity to my brother’s p3nis.”
My sister’s pvssy is hot and slippery, writhing and twisting around my d1ck. She tightly grips the sheets, not showing any sign of pain as she accepts my d1ck deep inside.
“Mmm… haah… amazing, this is a woman’s raw pvssy… I’m really engaging in incest with my sister…”
“Come on, don’t put it like that. Just say s3x normally.”
“You’re the one who said “I’m losing my virginity to my brother’s p3nis” after all. Anyway, for a slave, you’re acting pretty cocky. Well, since you served me properly with pvssy, I’ll reward you with a kiss. Now, stick out your tongue.”
My sister stuck out her tongue and entwined it with mine. She said it was her first kiss, but she’s being so aggressive from the start.
“Mmm… smooch…”
“Mmm… phew… nom…”
“Sis, you’re really good at kissing, but is this really your first kiss?”
While moving my hips, I ask my sister, who has a melted expression on her face beneath me.
“It’s my first time with a man… A junior confessed to me, begging just for a kiss, and I couldn’t say no. So I have experiences with girls, though. But you, why are you so used to this?”
“Huh? Well, I haven’t had s3x yet, but I do have a girlfriend.”
“Huh? I haven’t heard about this!”
“Well, we’ve only been dating for about a month, and I was keeping it a secret.”
“…Break up with her. I was the one who gave you my virginity first, so it’s rude to that girl.”
“But sis, you’re only going to be a s3x slave for today, right?”
“I will only be your s3x slave just for today… but from tomorrow, I’ll be your s3x friend… or, well, I could also be your girlfriend if you want.”
She kind of mumbled that at the end, but does this count as a confession, even though it’s not clear?
“Alright, then from tomorrow, I’ll turn you into my s3x friend and break up with my girlfriend.”
“Huh? Were you even listening? I said I’d be your girlfriend too, you know?”
“I mean, suddenly having my actual sister as my girlfriend all of a sudden is a bit much. When I get used to calling you Riko and you can properly call me Masaki, then I’ll become your boyfriend.”
“Seriously… you’re such a selfish little brother. I wonder why I ended up liking someone like you.”
My sister wrapped both hands around the back of my neck and hugged me, then started moving her hips back and forth. I grabbed her hips and began thrusting harder. With a soft, rhythmic pressure, her pvssy tightly squeezes my d1ck and I can’t stop moving my hips. We kissed, massaged her br3asts, traced our tongues over each other’s necks, and savored the s3x together.
“Mmm… ah, it feels so good when you thrust deep inside.”
“Riko, I can’t hold back anymore, so I’m going to cum inside.”
“It’s fine, cum inside… ejaculate your semen inside and make it a sticky, used pvssy, Master.”
My sister entangled her legs around me and firmly pinned my waist down. Calling me ‘Master’ right here would is cheating. I pressed my waist against hers and then, without hesitation ejaculated with all my might.
“Mmm, ahh… It’s coming out… My brother’s semen, it’s really been poured inside me…”
A large quantity of semen is gushing out of my d1ck. Her pvssy wriggles as if to gulp down the massive amount of semen greedily, squeezing it out with an intensity that ensures not a single drop is lost. The overwhelming pleasure made my mind go completely blank. Is this what s3x is like, cumming inside?
“Hah… that was so amazing…”
“I enjoyed it too.”
We stayed in each other’s arms for a while, savoring the afterglow. My Sister’s pvssy is dripping the semen I ejaculated inside her, and honestly, it’s pretty erotic.
“Riko, how do you feel about me ejaculating inside you?”
“It felt like I became my little brother’s woman, and the sense of being conquered was overwhelming.”
My sister presses her br3asts against me, smiling at me with a very seductive expression.
“Hey, we can do it again, right? This time, I’ll wear my basketball uniform, so you can cum inside me like before, or you can cum on me. Since it’s your birthday Eve today, I’ll stop after this, but tomorrow, I’ll be your s3x slave from morning until night. You better appreciate it, Master♡”
My d1ck starts to stir again just from those words. I never knew my sister was so sexy and liked me this way. Our new relationship has only just begun.
Chapter length 7062 characters.
TL Note: This series is part of my birthday release! My current ongoing series have received some extra chapters along with a few new series! Make sure to check them all out!