John’s life was in what most of his ilk would call a ‘transitional phase’- meaning he didn’t have a job and was kicked out of his apartment. He knew life after collage wasn’t going to be easy, much less fair, but it was being an absolute dick to him at the moment, even though it had been two years since collage. His family graciously invited him back home for a little while until he could find another job and a place to move in to. Until then, his parents had plenty for him to do in terms of yard work and other household chores to keep him from being a complete freeloader. 
John was the oldest of four kids: one brother and two sisters, Michael, Jenna and Grace. Jenna was 23, two years younger than John, and was actually in a better state of affairs with her living space and job security. Michael was 18, had just graduated from high school and was all set to start college in the fall. And finally, bringing up the rear was Grace at 15. 
During family outings, Grace tended to stand out. She liked having other people’s attention, had to be a part of everyone’s conversation, was very boisterous, and was the only canine in an all feline family.  That last fact alone was enough to let people know that she was adopted. She had been with the family long enough for everyone to consider her a part of it though; the fact that she was a little golden retriever girl with short-hair felines didn’t matter anymore.
Like some younger siblings might do, Grace tended to cling to John and seek his attention the most. And like most older siblings, John was usually annoyed by it. He knew better than to persistently tease her or shove her away though, especially by the age of 25, unlike Michael. She more than likely looked up to him not just because he was the oldest but because he was also the first to leave the house, as if it was to be considered an act of gallantry. Because the more considerate of her two older brothers was often away for most of the year, she celebrated his return more than everyone else.
Such was the case when she found out that John was coming home once again, but was likely to stay a little longer than usual. She couldn’t have been happier.
A couple weeks had passed since his arrival, and since then his time was mainly spent practicing, reading, working, and being a third parent when Grace and Michael got into another argument and Mom and Dad weren’t around. Being a resident instead of a guest again made him realize a few things he missed with his two youngest siblings in the last couple of years. Mostly it was how the both of them had changed in ways big and small both physically and mentally. Graces were the most noticeable; and, admittedly, more appealing. 
Whenever Grace would come to mind, John would mainly think of the hyper little puppy that had been with the family since she was three. She had obviously grown since then but her hyperactivity was still very much the same. That was what caused him to miss some of her developments in the past couple of years, because she still seemed to be the same annoying, attention craving little sister. However, lately her physical growth was starting to be taken note of by her oldest brother.
Though it was still in an early stage, her body had a form to it. Her natural athleticism had a little to do with that, but her natural stages of pre-womanhood made John, and most likely other boys, take a second look. 
He berated himself for even looking at her in such a way. Though she wasn’t related by blood she was still a minor. Even if she were 18 it would still feel weird to him… or would it? 
He tried his best not to think about it, but as the summer progressed and the typical mid-western temperatures blared down on them; Grace’s choice in clothing was getting way too suggestive. John couldn’t fathom how in the hell their Mom was allowing her to wear such short shorts in the first place, much less the tighter tops that made what curves she did have way more apparent than they should have been. She was obviously trying to wear something boy-magnet-ish with the excuse that it was so hot outside, but she seemed completely oblivious to the fact that it was starting to drive her oldest brother crazy.
John hated the fact that whenever he tried to crank one out in order to ease the tension, he would fantasize about Grace in progressively more provocative and lewd scenarios. He hated it even more when he couldn’t deny that he was enjoying it so much. It was ridiculous how hard he came when he thought about her, and it was getting harder to feel ashamed about it since it felt so good. Lately, he would often ask himself, “When did I become such a fucking sick creep!?”
His worst nightmare (or his dream come true as he would see it as later)  was realized when his parents announced that they would be gone for the weekend- something about being invited to a wedding of one of his Dad’s Client’s Daughter out of state. Michael was going to be visiting a friend for a sort of private LAN party that same weekend. So, since John had nothing else to do, he was asked to watch after Grace. He wanted to decline but (1) he had no feasible excuse to do so and (2) that secret part of him just kept screaming in his head, “SCORE!”
Friday evening was such a stress-fest at first. He couldn’t even look forward to the pizza baking in the oven, and there wasn’t any booze in the house to calm his nerves. He did his best to just stay many paces away from Grace, if not just in a completely different room. He still made sure to uphold his duties as ‘Weekend Parent’ to check up on her every once in a while, but it was only a brief glance to make sure she wasn’t burning the house down or anything and back to being scarce. 
He was able to at least find some solace from his guitar, though concentration still waned at times. Then the inevitable happened, and he heard a few quick raps on his bedroom door. He sighed, mostly in annoyance as he called out to answer. “Yeah?”
“Hey John?” Grace’s slightly muffled voice called back through the door. “Can we watch a movie?”
“You can watch a movie. I’m a little busy.”
“But I wanna watch it with you! Please?”
“No!”
He knew it would be the end of him if he ended up having to sit with her, in the same room, alone, for over two hours. He would be a ticking time bomb in there, and there weren’t gonna be any wires to cut or codes to enter in order to defuse whatever situation could develop. But, as usual, Grace wasn’t going to take ‘No’ for an answer.
“C’mon John, we never get to hang out like this!” she whined, jiggling the door handle even though it was locked.
“There’s a reason for that you know.” Though obviously the biggest one at the moment was one she had no idea about. 
“I promise not to bug you or anything! Please? I just wanna hang out!”
“Call a friend then! If their parents are okay with it then so am I!”
“All of my friends are busy though.” That seemed unlikely, but then again he didn’t really know her friends. “Besides, I wanna hang out with you right now.”
“Not gonna happen!”
“C’mon! Please?”
“No!”
“Please!”
“No!”
“Please!” 
“No!”
“Pleeeeeeeeeeease!”
The volleys continued for a short while longer, much longer than expected. Normally if she wanted something she would have given up with him already, but she was being much more persistent this time. She sincerely wanted to spend time with him for once, and while it would have been rather uplifting before, now it seemed almost more annoying that her usual pestering. The one time she wanted to be an affectionate little sister and just hang out with her big brother was the time when said brother found her to be a major cock-tease!
As much as he wanted to resist, it was getting more and more obvious as time went on that she really wasn’t going to give up this time. With a heavy sigh, he set his guitar on its stand, turned off his amp, and then walked up to unlock his door. On the other side Grace stood bouncing on her toes excitedly with a hopeful look in her eyes. John rubbed his eyes with a groan of defeat before he looked down at her again.
“What movie?” He asked without the slightest hint of enthusiasm.
“Yay!” she yelled as she hugged him tightly. While her breasts were likely not to their full potential, they were still big enough for him to feel them squish against his midsection. He prayed to God that she wouldn’t feel the boner that was threatening to rip his jeans apart. 
“I wanna watch Kill Bill!” she announced as she pulled away from him.
John cocked an eyebrow, surprised for once. “Since when do we own that?”
She looked away innocently as she twiddled her fingers. “Well, I actually borrowed it from one of my classmates. I’ve always wanted to see it!”
Under normal circumstances he would have said no; but he had a thought. There was so much over-the-top violence and blood effects in both parts of the film that he figured it could be enough to keep his arousal at bay. With that in mind, he answered, “Okay… why not!”
She lit up again, smiling ear to ear. “Awesome! I’ll go get some popcorn ready!”
Her tail wagged sporadically behind her as she ran off downstairs, and he couldn’t help but stare at her butt in her tight shorts for a moment. He suddenly realized he was smiling slightly, but told himself it was because of her hyperactivity rather than her cute butt.
Minutes later they were set up in the living room, each with a big bowl of popcorn. Much to his dismay, John realized that keeping his eyes on the TV was going to be more difficult than anticipated. Instead of taking the opposite end of the couch, Grace was snuggled belly down on the large beanbag that usually sat in the corner of the room. Her firm, teenage ass was in full view with her tail wagging high in the air. He cursed his bad luck and her obliviousness. While he had the power to tell her to just sit on the couch instead, his salacious side was getting the better of him. 
Admittedly, the movie did do the trick in keeping him from looking at her very often, but it would have been more effective is she wasn’t lying in front of the couch with her ass facing him. With the chaotic action of the first movie he was at least able to keep his boner in check. After part 2 started though, things were much harder to manage. He should have anticipated this, but his mind was too focused on not staring at her butt at the time to really plan ahead. As the plot moved along his eyes drifted more often, and for much longer, to her pert young ass. She was so zoned out watching the movie, as she tended to do with about any movie, that she never noticed him even once. 
The tightness in his jeans was getting more and more uncomfortable by the minute. He tried to adjust himself but even that wasn’t doing the trick. It was a raging boner that made previous ones feel like half-chubs, and it wanted out! John was starting to breathe a little more heavily now and his face grew hot. His fingers twitched, itching to undo his pants button and fly. The internal struggle between responsibility and modesty against the need for sexual relief right then and there was nearly palpable. It was like there was an actual game of tug-of-war happening between common sense and desire. It was a valiant effort to stay composed, but he snapped eventually. 
Quietly, he undid the clasp of his jeans and slowly pulled the zipper down. He nearly sighed audibly at the sudden relief of pressure, his boxer-briefs pushing the denim opening further apart as his throbbing erection tried to push itself free of its cloth prison.  Still trying to move a slowly and silently as possible, he scooted out of his pants just enough to let his cock finally poke out. 
His breathing started getting shakier with nerves, hardly believing that he was going through with this. His hand was just as shaky as it lightly grasped his shaft. He bit down slightly on his other hand to keep himself from making any vocalizations or louder gasps. He stared lightly stroking himself as he stared at her ass.
The sensation felt better than he could have imagined, now that he wasn’t relying on his mind’s eye. It took everything he had not to groan, and he was nearly biting down hard enough to draw blood. Composure and control were both nearly impossible to maintain in that moment and his eyes stayed focused on her ass so much that he wouldn’t have even known if she was looking over her shoulder at all. The sound from the TV seemed muffled and far away, and any comment she could have made would have just sounded like another garbled bit of dialogue for all he knew. 
He had no idea how long he even lasted, but the bursting point came from out of nowhere. With a quick grunt his jizz shout out harder than any previous time he had ever stroked himself before. For one blissful second he was able to revel in his sweet relief… until he saw the trajectory of his seed. His heart jumped into his throat and nearly made him choke when the sticky rope of fluids landed across her bare foot and up her leg. He would have been impressed with his range if he hadn’t have been suffering from a heart-attack at that point. Grace suddenly jumped at the sensation, lying stiff and motionless for a second. It was at least enough time for John to shove his dick back in his pants and frantically fasten them again, but Grace would surely have seen him flailing for some weird reason. 
Grace stared wide eyed for a second at her leg and then up at her brother. Before she could even ask ‘What was that!?’ John was already on his feet and frantically bolting out of the room. 
“WellIthinkI’vehadenoughDon’tstayuptoolateNIGHT!” 
John clambered hysterically to his room and locked the door behind him. He sank down to the floor gasping for air, his heart refusing to stop pounding inside his chest. ‘I’m so boned! I am so boned!’ was the only thing that went through his mind as he sat their panting and panicking. He half expected to hear Grace fumbling with the phone outside to call their parents, but it was eerily silent beyond his door; from what he could tell at least. He just sat there, uncertain o what he should do. Many possible actions came to mind, but his body was unwilling to move at all. The silence outside did nothing to calm him. At least if Grace had screamed he would have had an idea of whether she was scared or furious. But there was nothing, not even a creak from the stairs or floorboards of the house. Just the heavy puffs of his breathing and the thump of his heart. 
He sat there for what felt like hours in frantic thought, calming at least a little to try and plan something out until he heard a small knock on his door. His heart was back in his throat, and he stopped breathing for a few seconds. He felt petrified, but jumped at the sound of Grace’s timid voice. 
“John… can… can we talk?”
‘I’m a dead cat!’ he thought to himself. He couldn’t foresee any sort of positive outcome from this after what just happened downstairs. He was sure Judgement day would reign down upon him if he opened the door. He just sat their stiffly and silently, frantically going back and forth from just biting the bullet and opening the door or just continue sitting there like a statue until the weekend was over. Something would happen eventually, but his willingness to act, or his lack of it, would likely determine what ‘it’ was…
To be continued… maybe?