Content warnings specific to this chapter: Incest(between sisters), cum inflation, futaLoli on FutaLoli, knotting. Author's Notes: This was the first chapter actually written, though chronologically earlier chapters were already planned. Other than that, not much to say. Futanari Outbreak by Imouto Kitten Chapter 5: Little Sister's Payback. It is the middle of the night when Poppu wakes to a tight, uncomfortable feeling in her underwear. Throwing off her covers and setting up, she lifts her yellow, eighth note-patterned night gown to discover that the penis she had just grown earlier that day was threatening to tear its cotton confines asunder. Thinking to herself, she curses her predicament 'Dammit, I swore I milked a full liter of that white stuff from it before going to bed, and it still wasn't enough to sate the urge for the night.' Exasperated, she removes her panties, being careful not to let them rip from being stretched by the unnaturally large member that was sticking out between her legs where her clitoris was supposed to be. Wrapping both of her tiny hands around the thick male organ, she starts to stroke in the hopes of being able to get back to sleep in time to be rested come morning. 'I hope Sayaka-chan is feeling up to another ride on my cock tomorrow. Her tight little cunny feels so much better than using my hands, not to mention all the cute sounds she makes when my cock goes deep inside her.' Thinking of her childhood friend recently turned lover, Poppu can feel herself on the verge of cumming. Not wanting to make a mess of her bedding, she quickly gets up off the bed and points her penis at the small wastebasket by her desk just as thick strands of milky white semen start shooting out of it. After about thirty seconds, the stream slows to a dribble, and Poppu uses some tissues from her desk to wipe away the excess cum clinging to her tip. Panting from the exertion, Poppu thinks to herself, 'man, it feels incredible everytime I have an eruption like that, but it doesn't feel like I am any closer to this thing going limp and letting me go back to sleep.' She then gets a devilish smile as she continues, 'Maybe I should take this as an opportunity to get Doremi back for the other night.' Pulling down her night gown to cover her penis and not bothering to put on new underwear, Poppu walks out of her bedroom and tip-toes down the hall to the room belonging to her older sister. Entering the older girl's room, Poppu finds Doremi sound asleep, sprawled out on her bed, covers kicked aside, her body turned sideways, and her legs dangling off the side of the bed. 'Well, that makes things a bit easier, she is already practically in the position i want her.' Poppu thinks, a pleased smile on her face. She gently removes the older girl's pajama bottoms and panties, being careful not to wake her. With the same care, she places Doremi's rear end right on the edge of the mattress, spreading her legs to the sides. Poppu then pulls her own nightgown over her head before dropping it in a pile with her sister's clothing. Looking down, she notices that her penis seems to have grown some since she left her own room and seems to be even harder. 'Did you grow in anticipation of fucking my sister?' She thinks as if talking to the thick member between her legs. She walks over to where her sister still sleeps and places the tip of her engorged cock at the older girl's opening. 'Just as I thought, placing her ass on the edge of her mattress puts her cunny at the perfect height for me to fuck her from a standing position.' Poppu thinks to herself, a wide grin plastered on her face. It is at this time that she notices Doremi's flaccid penis just above where her own is poised for penetration. 'Its a lot smaller than when she used it to steal my virginity the other night. I guess it shrinks by quite a bit when it goes limp. I hope what I am about to do to her cunny leaves her with an insatiable erection for the rest of the night.' With that thought, Poppu loops her arms under the older girl's legs, knees coming to rest upon elbows, and holding them apart, rams her thick member into Doremi's vagina all the way to the hilt in one thrust, not caring if the sudden, unprepared intrusion hurts the older girl. 'Oh my god! She's so much tighter than Sayaka-chan. I nearly lost it just from sinking myself to her cervix.' Noticing that Doremi is still asleep, she continues her thoughts, 'I knew she was a heavy sleeper, but this is rediculous... Well, lets see how much I can abuse this hole of hers before she wakes up.' With that, Poppu slowly retracts her penis from her sister until just the head remains within the older of the two before thrusting back in with tremendous force. Repeating the motion, the younger girl sets a pace that would leave any normal girl screaming in pain even from a normal-sized cock whereas Poppu's already unnaturally thick member continues to gain girth, stretching Doremi's internal walls to an extent normally only seen during childbirth. Groans expressing a mixture of pleasure and discomfort can be heard from the older girl, and half opening her eyes, Doremi says in a drowsy tone, "Akatsuki-kuuun, why are you being so rough?" Looking down between her legs, she realizes that its not her wizard Prince making love to her, but rather her younger sister who is sporting a massive cock she did not have the last time Doremi saw the younger girl naked. Snapping to full wakefulness at this realization, Doremi raises to a semi upright position, propping herself up on her elbows, the firm grip on her legs and the male organ invading her birth canal preventing her from assuming a proper sitting position. Outrage apparent in her tone, but keeping quiet as to avoid waking their parents, Doremi questions her younger sister, "What the hell are you doing Poppu?" Not slowing down, Poppu replies in a callous tone, "I see you're finally awake, Onee-chan, and if you must know, I was woken up by some nocturnal wood and decided some payback was in order for you stealing my virginity the other night." Taking a good look at what is going on, an expression of shock and fear grows on Doremi's face as she takes in every detail. She can clearly see a prominant bulge that starts right above her flaccid penis and expands up her lower abdomen with every inward thrust of Poppu's hips followed by the skin sinking down when the younger girl pulls back, and it is on these outward strokes that Doremi gets a good look at the monster her sister is fucking her with. By Doremi's best estimate, it has to be at least 15 cm accross at its widest and the shaft alone is easily 30 cm in length. The head always remains completely within her, but Doremi knows it must be larger than any newborn's, yet instead of pain that would make childbirth seem pleasant that she would expect from being stretched to such an extent, all she feels is an extreme fullness followed by abject emptiness. Fear evident in her voice, Doremi asks, "When did you get a cock and how did it get so huge?" Poppu replies, her tone even despite her being covered in sweat from the exertion of violating her sister's hole, "It sprouted during gym class today, and at first, it was no bigger than yours had been when you first penetrated me. When Sayaka-chan help me relieve that first erection in the girl's restrooms, it grew inside her, but no more than yours had when you fucked me the other night. It only started growing to such a ridiculous size after I started fucking you." Still frightened, Doremi states, "Is is it still growing? I don't want it to tear me apart." Poppu responds, "I don't think its grown any since you woke up, and it feels like its gotten about as thick as it can and still fit between the bones of your pelvis. Besides, since there is no blood on my cock and I haven't reduced you to crying in agony, I am going to assume I am not hurting you." Her worries somewhat alleviated, the fear of pain and injury gives way to embarrassment at being fucked by her younger sister, a blush replaces her shocked expression as Doremi speaks in a hushed tone, "Well, I know something that large should be shredding my insides, but I have to admit that it actually feels kind of good." A cheeky grin on her face, Poppu replies, "So onee-chan likes getting fucked by her little sister? Are you an imoutocon or something?" With indignation in her voice, Doremi exclaims, "Its not like that!", but in spite of her protests, her internal walls tighten around Poppu's penis as her own member comes to attention. "Your mouth says no, but it feels like your cunny really wants my cum, and I bet your own penis awoke at the prospect of switching places when I finish filling you up." the younger girl retorts as she reaches out to grab the older girl's penis, giving it a few gentle strokes As the nerve impulses from Poppu's touch reach her brain, Doremi finally gives into the pleasure and lets out a lustful moan before saying, "Poppu-chan, please keep stroking and fucking me. Please make me come." Letting out another moan, she lets herself fall back on to the bed as her eyes glaze over in bliss. As she does so, the walls of her vagina start rhythmic contractions as if to massage the penis they are wrapped around. Letting out her own moan, Poppu replies, a devilish tone in her voice, "I will gladly fuck this hole of yours until my cock erupts with thick streams of hot, gooey cum, which shouldn't take much longer with how your cunny is trying to milk my cock, but I have no interest in ensuring your enjoyment and actually hope your erect cock keeps you up the rest of the night." With that, Poppu removes her hand from the older girl's member,and shifts the older girls legs to rest on her shoulders. Grabbing Doremi's hips and leaning forward to put more weight behind her cock, Poppu thrusts in again, but instead of pulling back, she keeps up the pressure as the head of her cock presses against Doremi's cervix. Somewhat panicked, Doremi asks, "Wh-what are you trying to do?" Poppu respondes, "I'm going to fuck your womb." At that moment, Doremi's cervix gives way, allowing the head of Poppu's monstrous cock to pop into the older girl's uterus, the ring of muscles that had served as the final barrier against such deep intrusion forming a tight seal around Poppu's member where head meets shaft. Letting out a shriek at having her body's inner most sanctum invaded, Doremi shouts, "Get out of my womb!" Poppu tries to pull out, but Doremi's cervix is squeezing her cock so tightly that, instead of the head popping back out of Doremi's womb, It drags Doremi's womb with it, the older girl's vaginal walls scrunching up as Poppu retracts her penis. "Looks like my cock head is stuck in there. Oh well, I am going to enjoy cumming directly in your womb." Poppu replies, not the least bit bothered by being stuck. As Poppu resumes her thrusting, setting a faster pace than before, Doremi is overwhelmed by the sensations caused by her womb being forced to move with the head of the cock that is inside her. Meanwhile, the older girl's penis is throbbing painfully for some attention, but when Doremi reaches down to stroke her own hardness, Poppu grabs her wrists to prevent the older girl from masturbating. "Please let me jack-off if your not going to give me a hand job while fucking me." Doremi whines, trying to free her hands from Poppu's grasp. "Sorry, onee-chan, but only my cock gets to enjoy this encounter, and speaking of enjoyment, I think I am on the verge of unloading a huge load of semen." Poppu manages to get out while panting for air. A few strokes later, Poppu makes one final thrust, burying her cock entirely within her older sister. Doremi feels the base of her younger sister's cock swell within her and realizes that not only is the head stuck within her womb, but now the shaft is stuck within her passage. Before Doremi can dwell on this, however, she feels a powerful, continuous stream of semen erupt from the cock head that is buried deep within her. Overwhelmed by the initial euphoria from her orgasm, Poppu's entire body goes limp and she slumps forward, the position of Doremi's legs being the only thing preventing her from collapsing on top of the older girl. Her hands freed in the process, Doremi moves to rub her belly where she can feel her womb being filled by her younger sister's semen. Feeling a fullness in her womb, Doremi can no longer feel the jet originating from Poppu's urethra, it having been lost in the pool of cum inside Doremi's womb, but the older girl can still feel the pool expanding. With her cervix forming a seal that prevents any of the cum from gushing into her vagina, Doremi's womb stretches to accomodate the load. Doremi can feel and see as her belly starts bulging to accomodate her cum inflated womb. Shock on her face and panic in her voice Doremi pleads, "Poppu, you need to stop coming in me!" Brought back to her senses, Poppu tries to halt the flow like she would when peeing while trying to remove herself from her sister, but to no avail. "I can't stop cumming, and I am completely stuck." the younger girl says, the slightest bit of worry in her voice. Rubbing her belly, which has bloated to the size of a basketball, the older girl retorts, "I already look pregnant from all the cum you've put in me, and you're telling me that I am going to have to endure being pumped full of even more until that cock of yours decides to stop?" Poppu responds, "Looks that way, though I have to admit, onee-chan looks quite sexy with such a big belly, especially since I am the one that caused it. Makes me wonder if my cum can get onee-chan pregnant." Anger in her voice, Doremi retorts, "Don't even talk like that, incest is bad enough without producing children, besides, your no where near puberty." Rubbing her now beachball-sized belly and speaking in a softer tone she continues, "I do have to admit that being so full of cum is surprisingly comfortable. I would have thought having my womb stretch so much so quickly would have been excruciatingly painful. "Well, if you do get pregnant from this, I call dibs on your milk when you start lactating." Poppu responds in a teasing tone. "and by the way, I think I stopped cumming, though I think we are going to have to wait for my cock to shrink some before I can pull it out. "Yeah, it does feel like the pool has stopped growing." Doremi says rubbing her belly that looks like she is ready to give birth to triplets. "If all this cum does end up fertilizing some of my eggs, I hope you return the favor one day." she adds teasingly. "Well, I hope you don't get to attached to having sex with me, onee-chan." Poppu states. "I do have a girlfriend now, and I plan to give most of my cum to her. This was just payback for you stealing my virginity." With that, both girls notice that Poppu's knot has gone down and her cock has lost some girth, being only about 10 cm accross at its widest, yet Doremi's pussy feels as tight as ever around it. Poppu starts to pull out, and this time, Doremi's cervix allows the head to slip out of Doremi's womb. No longer held open by Poppu's cock, Doremi's cervix quickly shrinks and forms a new seal before any cum can leak into her vagina. When she pulls her cock completely from Doremi's pussy, Poppu is surprised that a deluge of semen did not follow. "Looks like my cock wasn't the only thing plugging you up. At least this avoids the mess." Poppu says, ending with a little giggle. Looking down at her cock, Poppu notices that it is back to the size it was when she woke-up, long and thick, but still within normal for a human cock. It glistens with Doremi's juices with only a few drops of semen around the tip. 'Dammit, I'm still hard, even after filling Doremi's womb with an amount of cum that screams magic.' climbing onto the bed, Poppu kneels above Doremi's face before speaking. "I need you to lick me clean." Doremi responds, "but what if you release another deluge, I could drown getting that much to the face." "I doubt I could release another load like that so soon. Besides, you can either suck me off or we can see if your rectum is as elastic as your vagina and womb." Poppu responds. Having no further protests, Doremi opens her mouth wide for the younger girl's cock. Burying her small hands in the older girl's oversized odango, Poppu starts thrusting into the older girl's mouth, desperate to finish this quickly so she can go back to bed. It only takes a minute or two before Poppu releases a normal sized load in her Sisters mouth, and after giving Doremi time to suck out all of it, Poppu pulls her finally flaccid cock from Doremi's mouth. "I think I am finally satisfied." Poppu states and she gets off the bed and starts pulling her nightgown back on. "Good night onee-chan." Before Poppu can leave, Doremi asks, "What about my cum inflated belly and my own untouched erection?" Poppu replies nonchalantly, "I'll leave those to you to figure out. I will tell you one thing, you aren't getting any pussy from me tonight, or any night for the foreseeable future." "How can you be so cruel?" Doremi whines, fake tears welling up in her eyes. "If your that desperate, you could always try seeing if Dodo would be willing to help you out." and with that, Poppu leaves the room, leaving Doremi in nothing but her pajama shirt with a cum-inflated belly and a throbbing erection.