A Good Big Brother by ImoutoCommissions

You wake up to a familiar sensation, finding that Onpu has spooned up 
with you, and is grinding against you. You're already hard, and the 
feeling of your little sister's butt grinding against your erection 
tells you how you got to that point. She wiggles in her sleep, and you 
smile fondly to see that she has found her way back into your bed once 
again.

Finding her in your bed has been a rather common occurrence for years, 
especially on nights when your parents are out of town or working late, 
but eventually, it started to stir up new feelings within you. In recent 
months, it has become a lot for you to deal with, having one of the most 
desired girl's in the country in your bed. As your little sister, she is 
not someone you should feel such things for, and yet, you have not been 
able to help yourself at any point, and you began doing whatever you 
could to help with those feelings.

~X~

Months earlier, you sneaked into her bedroom just to be able to watch 
her sleep, feeling guilty about your fantasies. You knew that you were 
thinking about the same way all the boys and perhaps some of the girls 
in her fan club do, and now, her photo albums were not enough for you 
anymore. You needed something else to assist in your fantasies, to keep 
your forbidden desires for your beloved little sister in check.

She looked so cute curled up in her bed, the picture of perfect 
innocence. She sucked her thumb, the covers kicked aside to reveal her 
lavender pajamas, with her bare feet tangled up in them. The picture of 
perfect innocence, and a sharp contrast to her you, perverted older 
brother. You pulled out your cock and began stroking yourself off to the 
scene in front of you, willing to do whatever it took to get yourself 
off to her. How could you help being anything other than smug? After 
all, you get to see her in such a vulnerable state, in a way none of her 
little fans are ever going to get to.

Just when you were on the verge of losing yourself to your climax, Onpu 
suddenly squirmed, making you freeze, terrified that you were about to 
be caught in the act. When she sat up, you really thought that you were 
doomed, but she rose from her bed without reacting to your presence at 
all, and when she walked right past you, you realized that she must be 
sleepwalking.

Curious, you followed after her as she went to the bathroom, and resumed 
stroking yourself as she pulled down her pants and panties, sitting on 
the toilet and parting her legs just enough to give you a peak. Between 
that sight and the sound of her peeing into the toilet, there was 
nothing that you could do to fight off your release, cock erupting all 
at once. At that point, you had to set to cleaning up, and became so 
distracted by this that you did not even notice Onpu leaving the 
bathroom until you looked up to see that she was gone.

Returning to your own room, you found her there, blindly groping around 
in your bed as if searching for you. Of course, even in her sleeping 
walking state, she would want to find comfort with her big brother, and 
you realized then that this was how she so often found her way to your 
bed in the night. And so, you settled in with her, so that she could 
cling to you. It did not take long for you to fall asleep with her, 
satisfied with everything that had happened that night.

~X~

And now, back in the present, you have slipped your hand down her pants 
and have the other up her shirt, teasing at her nipple and fingering her 
cunny, making your little sister moan in her sleep. Sometimes, in her 
sleep talk, she moans out, "Onii-chan..." She has no idea what you are 
doing to her, and yet, she still instinctively moans for you when you do 
it.

~X~

Not long after you discovered that incident of sleepwalking, you 
realized that such a thing was a nearly nightly occurrence, finding it 
easier to sneak into her room and just watch, until you began to grow 
even more bold. You could touch her here and there, in subtle ways that 
you were sure you would be able to pass off, if she happened to wake up 
during that time. However, she never did, and that made it even easier 
to get bold with her, willing to do whatever you could to get closer to 
your sweet little sister.

You also discovered that her sucking her thumb was frequent, almost 
constant, as if she needs something in her mouth to be able to sleep 
peacefully, as if sucking in her sleep is the most base of instincts for 
her. With that sort of thought in your mind, there was no way for you to 
resist the urge to see what would happen if you pulled her thumb away 
from her mouth. Just as soon as you had the tip of your cock pressed to 
her lips, Onpu was ready to latch on, not missing a beat, just eager to 
have something in her mouth once again.

She started sucking on you like a starving infant might suck on a 
bottle. It was all you could do not to moan out for her, biting it back, 
afraid to do anything that might wake her up while she pleasured you so 
perfectly. Even without knowing what to do, just acting on instinct, it 
all felt perfect to you, and you let out a soft sigh rather than 
moaning. You knew in that moment you really did have her, in ways her 
fanclub never would. Hell, you're the number one, not settling for 
anything else, and while letting her suck your cock in her sleep, you 
knew this was something only her biggest fan could ever deserve.

And then you came, sudden and hard, flooding her mouth with your seed, 
and you did not even have time to panic before she had already swallowed 
it all down. The good girl did everything so reflexively that it was 
perfectly natural, and none of it so much as made her stir. However, not 
long after you pulled out of her mouth, she started to squirm, as she 
often did before getting up to sleepwalk and go pee.

You decided then that you should return the favor, helping her out as 
she had helped you. You grabbed hold of her hips and pulled her pajama 
pants down, admiring her plain cotton panties and the way they hugged 
her cute little pussy. Your admiration was cut short when she began 
squirming again, and you reminded yourself that you were on a mission 
right now, that you had more important things to take care of.

You pulled her panties down as well to put your face between her legs. 
As you started gently licking her, she gave into the demands of her 
bladder and began peeing into your open mouth, sighing softly in her 
sleep. Ever the dutiful older brother, you drank it all down.

~X~

Tonight, you swiftly roll down her pants and panties over her butt, so 
that you can slide into them, pressing the tip of your cock against her 
cunny. Like this, it is easy for you to remember the night you first 
took this step, the night that you took her virginity, all completely 
unbeknownst to her.

~X~

It came after several nights of eating her out, getting bolder about 
undressing her more and more, to fondle more of her body. You had gotten 
to the point that you could not handle just drinking her pee and 
stopping. You wanted more, and on this night, you were doing this to get 
her warmed up for you, so that you could take it. By now, you knew that 
she was not going to wake up for anything.

After all, she had been so tired all the time. Her schoolwork and work 
as an idol were bad enough on her, but ever since becoming a witch 
apprentice, things were even more exhausting for your dear little 
sister. Though she did not know you were aware of her double life, you 
had known for quite some time. You never told her that you had 
discovered her secret, though you did help cover for her with your 
family, whenever she might need you to.

With all those things piled up, it only made sense that she was also 
this tired, so tired that she slept through the night, not even fully 
waking up to go to the bathroom or come to your bed, her body always 
moving on autopilot. Even so, you knew that you had already gone much 
too far with what you had been doing to her in her sleep, but your cock 
throbbed, desperate to be inside of her, and you were not able to resist 
that urge, not even for another moment.

"Please forgive me," you softly murmured, as you pressed the tip of your 
cock against her pussy. Slowly, you pushed into her, finding that she 
was so much tighter and warmer than you ever could have imagined, that 
everything about her was more perfect than you could have imagined.

At first, you were still within her, pushing her pajama top up to 
lovingly caress her skin, but as your desire caught up to you, you knew 
that you would need to start moving. You were slow as you began making 
love to your little sister, making her moan softly in her sleep. As you 
felt yourself nearing your climax, it took all of your self-control to 
be able to pull out of her before you came. You made a mess of her 
tummy, but you licked her clean, making sure that you left no evidence 
of your activity.

You let her return the favor, putting your cock in her mouth to be 
sucked clean, before getting her dressed again. At that point, you went 
back to your own bed, not feeling nearly as guilty as you knew that you 
probably should. You were just too satisfied for that.

~X~

As you thrust into her, you are brought to the edge so quickly. You hold 
nothing back when it comes time for that, coming inside of your sweet 
little sister, moaning softly as you fill her up. That first time, you 
were afraid to come inside of her, but eventually you did lose control.

~X~

When you entered Onpu's room on this particular night, you found her 
hugging her pillow, laying on top of it with her butt in the air. All of 
that was far too tempting for you to resist, so you pulled her bottoms 
down, and skipped any sort of foreplay before pushing your cock inside 
of her. You have had plenty of time to learn what a heavy sleeper she 
really is, and knew that you could be fairly wild with her without her 
having any chance of waking up.

That is why you got into it right from the start, thrusting into her 
wildly as you worked out all of your pent up, incestuous lust, using her 
sleeping form to relieve it. However, like this, it did not take long 
for you to get close in that tight pussy of hers, and you wanted to make 
this last, wanted to enjoy this for as long as you could, so you slowed 
to a halt, trying to regain your composure before continuing.

However, at that moment, Onpu began to move her hips in her sleep, as if 
acting on instinct, sensing the lack of movement and wanting more. You 
panicked and tried to pull back, but her pussy seemed to clamp around 
you then, so tight it was like a vice grip, making it impossible for you 
to pull out before you exploded inside of her, filling her with your 
seed all at once, too dazed and pleased to react at first.

~X~

You want to fall asleep with your cock buried inside of her, but you 
know better than to do something like that. After all, she might wake up 
before you, and you have no idea how she would react to something like 
that. While you are thinking about this, Onpu starts to squirm in her 
sleep, making you realize that this must have been a night when her 
sleepwalking brought her to your room before it brought her to the 
toilet.

You pull out of her then so that you can switch positions, bringing her 
face to your lap, and putting your face between her legs, starting to 
lick out the cream pie you left within her while her lips latch onto 
your cock. She is still so good at sucking in her sleep, the reflexive 
movements everything that you could ever ask for. While she sucks you 
off, her bladder gives out, and you drink down every last drop of her 
pee. In return, you let your own bladder relax, knowing that she is 
going to return that favor, and drink down your pee as well.

Moments like these show just how close the two of you are, at least when 
she is asleep and you have complete control over her. You can think of 
no way you would rather bond with your little sister than mutually 
drinking each other's pee after fucking, and even if she is unaware of 
it, that does not change your enjoyment. You love her so much, her 
number one fan and her one and only big brother, the only person that 
gets to share in this side of her.

~X~

One night, you went to sit on the toilet to wait for her, wondering if 
things would play out the way you imagined them to. You were already 
hard for her, ready for her to approach you. And, right on schedule, she 
ambled into the room, empty expression, completely asleep and oblivious 
to the fact that her big brother was sitting on the toilet that she 
wanted to use.

Coming up to you, she turned around in front of you, pulling down her 
pants and her panties, showing you her perfect little rear, and you 
resisted the urge to reach out and start groping her. You did not want 
to alert her to your presence this way, waiting instead for her to go 
and sit on the toilet, pausing upon realizing that you were already 
there.

However, that did not throw her off too much, and in no time at all, she 
had figured out how she wanted to react, acting on a different sort of 
instinct in her sleepy state. Just as you had hoped, she moved to sit on 
your lap then, taking your cock right up her pussy, letting it fill her 
as she took her seat. You let out a happy sigh, relaxing as your little 
sister begins to bounce on top of you, riding your lap instead of 
emptying her bladder.

She brought you to orgasm rather quickly like this, the whole ordeal so 
much more exciting in the moment, in actually getting to experience it 
all firsthand. You had imagined this as a possible outcome, but your 
imagination could not come close to comparing to the real thing. Before 
long, you were coming inside of her, filling her up with your seed, a 
bit past the point of caring about that loss of control. Only at that 
point did her bladder give out, your sweet little sister peeing for you 
while you filled her up.

~X~

Every night, you have all sorts of fun with Onpu, trying different 
things with her, and knowing that she will go along with it in her 
sleep, that she will always find her way back to your bed. You love her 
so much, and are glad you have your way to be close to her without 
actually bothering her with your feelings, though you hope one day there 
might be something between the two of you when she is aware of it. That 
is not something you would have thought of back in the beginning, when 
you were still racked with guilt.

In the morning, she is embarrassed to wake up in your bed again, never 
recalling how she ends up there in the first place, but you are quick to 
assure her that this is no problem, that you never mind watching over 
her. However, before she can say anything else, she suddenly claps a 
hand over her mouth, overwhelmed by nausea and having to bolt straight 
for the bathroom.

You hurry after her to find her kneeling in front of the toilet, puking 
her little guts up. The poor dear must be very sick, and so, you come to 
kneel behind her, gently rubbing her back and saying, "Do you need me to 
call the school? I think you should take the day off to rest."

You hope that the stomach bug she has come down with is not too 
contagious. If she is sick, then you want to be able to take care of 
her, doing your part as her big brother. At this time, it still does not 
occur to you that there might be some connection between this illness 
and what you have been doing to her at night. Your losses of control, 
the way that you have cared less and less each time...you have no idea 
that all of that could be connected, not even thinking about that.

The only thing that you can think about right now is your poor, sick 
little sister, and the fact that the only one home to take care of her 
right now is you. You are going to have to do your best to make sure 
that she is feeling better in no time, just like any good big brother 
would.