Sister Training by ImoutoCommissions

Chapter 1

Aiko has plans to train Pop as her new little sister, but that means 
bringing her current little sister, and older sister to Pop, along for 
the fun. After all, she and Doremi have quite the history together, and 
in her eyes, it just does not seem right to leave Doremi out of the fun, 
when she could have both little sisters at once. Already, she has an 
idea about how she can start the training, in a way that will be fun for 
all three of them, so she is quite excited by the time the two of them 
arrive.

Naturally, she wastes no time in springing into action, ready to get 
things started without missing a beat. She casts a spell on them that 
immediately rids them of their clothes, stripping them down to their 
panties, before tying their arms behind their backs. Doremi is forced to 
her knees so that she and Pop are at the same level, and both girls have 
spreader bars at the knees now, to ensure that their legs are kept 
apart.

"Alright, here you go. Make sure you drink up and that you drink it all 
down," is the first thing that she actually says to either of them, 
before presenting both of them with a large bottle of Oy! Cola. Their 
arms are briefly untied to accept this. This is not really surprising to 
Doremi, given Aiko's penchant for piss play, and she is sure that Pop 
will be able to catch onto that fact pretty easily, given the context.

The girls do what they can to drink it as quickly as possible, and it is 
not until they have both finished it, and their arms have been bound 
behind their backs again, that she adds, "Those were spiked with 
powerful diuretics and aphrodisiacs. It's not going to take too long for 
either of them to start to kick in!"

Of course, she is right about that, and both sisters are soon squirming, 
from a mix of desperation and arousal, all brought on by the drink that 
Aiko has made them consume. All they can do is stay right where they are 
as Aiko begins to strip down for them, taking her time to do it, teasing 
it out to make them want her that much more, their wait agonizing.

Finally, she gets down to her underwear, straining to contain her 
bulging cock, and once she pulls her panties off, her cock springs free, 
so big and so hard that it is enough to make both girls' mouths water. 
Aiko is proud to show off for them for the moment, but she has more in 
store for them, and needs to get a move on, before the drugs she has 
given them prove to be too much for them to handle. It would be a shame 
to waste all the effort that she has put into this perfect little 
meeting, all because she couldn't stop flaunting for her two little 
sisters.

"Alright, now both of you are going to take care of your big sis, using 
your cute little mouths to do it," Aiko says. "Whoever does the best job 
is the winner, so I know my cute little sisters both want to do their 
best!" She knows how the two of them get, their sibling rivalry quite 
intense despite their age difference, with Doremi often finding herself 
losing to her younger sister.

It will be fun to see which one of them prevails, or really, it will 
just be fun to see the way they both put their all into it, both so very 
eager to please her and have the chance to get another victory over on 
her sister. No matter who wins, Aiko knows that she is the true winner, 
and so, she lets the two of them get started.

Pop takes the tip of her cock while Doremi starts licking along her 
shaft, with Aiko big enough for both of them to be able to service her 
at once. Needless to say, they are both quite good at what they do, and 
both really putting their all into it, not at all letting her down. With 
their combined skills, she knows that it will not take long for her to 
blow her load, but the biggest problem with all of this is that she 
really is not sure which of them is doing the better job.

"Switch off," she orders them, hoping that seeing them perform at both 
jobs might help to clear things up. Doremi takes the tip then, while Pop 
begins using her tongue and lips on her shaft, and yet, they are both 
still very good at this. Despite being used to Doremi's efforts, that 
does not make them boring, or anything like that, and while Pop is very 
good at what she does, it is not as if the newness really makes her 
stand out so much that she could be proven that much better. Their 
skills seem to be about equal, and there is nothing Aiko can do to 
increase her bias, meaning that she is completely unsure of who the 
winner will be.

She is no more sure by the time that she can feel herself nearing her 
limit, so she knows that she just has to make a decision. If there is no 
way for her to decide it fairly, and no bias making her want to pick one 
over the other, than the only real choice left for her is to pick one at 
random, which is exactly what she does. Pulling back from the two, she 
looks between the two sisters, both so eager to win out over the other, 
before grabbing hold of one, making her decision.

As she shoves her cock down her little sister's throat, she cries out, 
"Alright, you're the winner! Your prize is...this!" As she lets out a 
low, indulgent moan, she shoots her load, making the little sister of 
her choice swallow it all down, while pleasure washes over her.

Chapter 2

Pop does her best to swallow down everything that Aiko has to give her, 
until her climax finally starts to fade out. She pulls back so that she 
can fill Pop's mouth, saying, "You have to let me see it before you 
swallow." As she pulls back, Pop leaves her mouth open, showing off the 
load on her tongue, before she is given permission to swallow that down 
as well.

She removes Pop's spreader bar and then her panties, discovering just 
how soaked they are. "It looks like you couldn't even hold your bladder 
this long," Aiko taunts her, pointing out the obvious wet spot.

"I didn't! It wasn't...it's just pussy juice!" Pop protests, going red 
in the face at Aiko's accusation. Her bladder is still full and 
bursting, she hasn't lost control quite yet.

"Let's just do a little taste test, then," Aiko replies, before grabbing 
Pop under her armpits and lifting her up so that her pussy is at mouth 
level. A quick lick is enough to satisfy her curiosity and prove that 
Pop is telling the truth- as well as prove that she is more than ready 
to get fucked within an inch of her life.

She turns her around to lower her onto her cock, grabbing her knees to 
hold her thighs apart. This way, she can fuck Pop while still standing, 
holding her up and thrusting into her, making her moan as she begins to 
fuck her properly. While they are getting into that, Doremi lets out a 
whimper, drawing Aiko's attention to her.

"That's right...well, you can service your big sis and the good little 
sis with your mouth while you wait," Aiko orders her, and Doremi is 
quick to do what she has been told, well trained in this regard. She 
kneels with them, so that she can move her tongue along both of them, 
licking at Pop's clit, and moving to lick at Aiko's pussy and what parts 
of her cock are not buried inside of Pop. This keeps her busy, while 
Aiko continues with what she has set out to do.

"So, who beat me to your pussy?" she asks Pop, something that she has 
wanted to know for some time now.

"I'll...I'll tell you later," Pop whines. "Alone..." She does not want 
to admit to this in front of Doremi, but Aiko is not having any of that. 
As she begins to aim her thrusts more at Pop's bladder, she tortures her 
so that she can get her to admit to the truth. "Stop, you're going to 
make me pee!"

"You're not allowed to pee or come until you answer me," Aiko retorts, 
and when her orders are given, then they are as good as law to her 
girls.

Pop knows that she has no other choice but to cry out, "I've been 
whoring myself out to the boys at school since kindergarten! Before I 
was yours, my rate was five hundred yen a go, and I've been with pretty 
much all the boys from my kindergarten!" She pauses for a moment before 
adding, "I haven't had much luck lately, cos Erika has all the boys 
wrapped around her little finger."

Aiko can't help thinking about whoring Pop out herself, letting the 
bigger boys take her ass, while the little boys try so hard to satisfy a 
pussy that only Aiko is capable of satisfying. Since Pop has been such a 
good girl and done as she was told, though, now is the time for 
rewarding her.

"You can pee now, and do it in Doremi's mouth. Doremi, I want you to 
make sure you drink every drop," she orders. Despite how desperate she 
is, though, Pop can't just force herself to let go, far too nervous to 
do something like that. So Aiko just fucks her harder and harder, until 
she pushes her to her climax. At that point, there is nothing she can do 
to keep her bladder in check, filling Doremi's mouth with her pee while 
Aiko fills her womb with her seed.

Aiko sets her down, patting her and saying, "You're such a good girl, I 
have the perfect reward for you." With a quick spell, Pop now has a 
little cock, no more than four inches, so that Aiko can offer her pussy 
to her. Pop is quick to plunge into her, eagerly pounding away at her 
new big sister's pussy, while also eager to try and suck on her cock at 
the same time.

Just when Pop is on the verge of her first orgasm in such a manner, Aiko 
grabs her by the armpits, pulling her out. When Pop starts whining with 
her need, Aiko says, "Don't worry, I'll let you come- inside Doremi."

"Hey, I never-" Doremi tries to protest, but all it takes is a smack to 
the butt to silence her. Aiko lays her on her back and unties Pop so 
that she can remove Doremi's spreader bar and panties. Like this, she is 
free to do whatever she wants to her, and she thrusts into her sister. 
At the same time, Aiko comes behind her to claim Pop's pussy, so that 
every time Pop pulls back, she sinks down onto Aiko's cock, before 
thrusting forward into Doremi, finding the perfect rhythm that leaves 
her so lost in pleasure she does not even listen to the way that Doremi 
begs her to please not come.

It does not take long for her to reach her climax, and she does the 
opposite of what Doremi wants, filling her with her seed. This sends 
Doremi into her own climax, which means that she can no longer hold her 
bladder anymore, contents gushing out of her. For a moment, she is 
completely relaxed, until Aiko speaks up about the mess that she has 
made.

"How should we punish my naughtier little sister?" she asks Pop, and Pop 
grins, already starting to get ideas.

"I think there are plenty of ways that we can get creative with her," 
she replies, and Doremi knows that she is in for it now.

Chapter 3

As soon as Aiko reaches her climax, she pulls out and comes all over 
Doremi's face, giving her a nice facial. She sighs happily, and once 
that is done, she turns to Pop and says, "Now, come clean our sister's 
face off!"

Pop moves forward to do as she is told, disappointed that she lost, but 
not wanting to do anything to make Aiko want to punish her further. She 
licks her sister's face clean, tasting Aiko's seed, jealous of the fact 
that Doremi was the one to get the facial when she wanted it so badly. 
At the very least, she can enjoy it secondhand.

Aiko then removes the spreader bar from Doremi, before pulling her to 
her feet and bending her over the bed so much so that it crushes her 
overfull bladder. She pulls her panties down, discovering just how wet 
they are, and all she has to say is, "That better be pussy juice, or I'm 
going to be pretty disappointed that you already leaked!"

With that being said, she does not see any need to wait for Doremi to 
try and explain herself, instead pressing the tip of her cock up against 
Doremi's equally soaked pussy and thrusting forward, plunging into her 
and filling her all at once.

"Get over here and take care of me with your mouth!" she orders Pop, 
while she is relaxing, content inside of Doremi. Pop waddles over, 
moving as best as she can with her spreader still on, and kneels down 
between Aiko's thighs to do as told. She tilts her head up to start 
licking at Aiko's pussy, teasing her clit and reaching any part of her 
cock that she can get to, that is not buried inside of her biological 
older sister.

While she does this, Doremi starts to whine, "You're crushing my 
bladder, please! It hurts, you're going to make me pee!"

"You can pee any time you want," Aiko replies. "But Pop has to drink 
down every drop, so make sure that she's in position before you do it."

Pop is quick to move where she is supposed to, getting her mouth ready, 
much to Doremi's relief. It is not difficult at all for Doremi to let go 
then, sighing happily as she pees into her little sister's mouth, while 
Aiko continues to pound into her, pushing herself closer and closer to 
another orgasm. It does not take her very long at all before she is 
there, hilting herself within Doremi and flooding her womb with her 
seed.

She pulls out of her then, and reaches to pat her on the head, saying, 
"You're such a good girl, just like you always are. You make me so 
proud."

She moves Doremi to lay her on her back, before using magic on her. 
Doremi finds her wrists and ankles pulled up and out and bound, as if 
tied to the edges of a large rectangle. Not only that, but she finds 
herself growing a rather large and manly cock.

Aiko climbs on top of her to straddle her, sinking down onto Doremi's 
cock, letting it fill her pussy. She is big enough that it is not hard 
for Doremi to sit up a bit and lean her face forward, so that she can 
start sucking Aiko's cock at the same time. As Aiko moans for her, she 
begins picking up the pace, riding Doremi to push her closer and closer 
to the edge. Her lack of experience with such feelings means that it is 
not long at all before Doremi is close, but then Aiko backs off, careful 
with how she stimulates her, so that she can make sure to only edge her.

Doremi soon realizes what is going on, and quickly becomes pathetic, 
whining, "Please, please, let me come! I really need it! Big sis, 
please!"

However, Aiko climbs off of her instead, while Doremi is squirming for 
her, and goes over to Pop, removing her spreader bar and her panties. 
"You can come, don't worry. You're just going to come in our littlest 
sister instead!"

At that point, Pop starts kicking and screaming, protesting this even as 
Aiko picks her up. She carries her over, and her screaming is 
interrupted with a sharp gasp, as she is dropped down onto Doremi's 
cock. Aiko holds her shoulders down so that she is unable to get back 
off. At this point, Aiko pushes into Doremi's pussy, holding onto Pop 
from behind, so that she can bounce her up and down on Doremi.

Pop tries to find ways to turn Doremi off, crying out, "Come on, I'm 
your real sister!" and "What would Grandma think of this?" and even 
whining about how she has to pee, but at the same time, Aiko keeps 
urging Doremi on, ordering her to come inside of her little sister, and 
Doremi is more keen on listening to that.

Pop does not give up, figuring Doremi is just into it being real incest 
and into the fact that she has to pee, so she starts crying out various 
kinks she thinks will turn her off. "If you do this, I'm going to...to 
shock you or burn you, and hurt your pussy, and..." No matter what she 
tries, it does not bother Doremi. Most of these are things she has 
either done with Aiko or discussed wanting to do, so she is not 
bothered.

In the end, she does come inside of Pop, ignoring the way that she 
protests, and at the same time, Aiko comes inside of Doremi again. No 
matter how much Pop wants to pretend she does not like it, she comes 
right alongside them, so hard that she completely loses control of her 
bladder in the process, crying out as she wets herself.

When Aiko comes down from her high, she observes the mess that Pop has 
made and turns to Doremi, asking, "How do you think we should punish our 
naughty little sister?"

Doremi grins and says, "I have a few ideas."