It was raining out, and after the briefest of glimpses at the murky gray sky through the window, Jack decided that he wouldn't be leaving his room until his class that afternoon. He'd not yet been at college long enough for the novelty of laziness to wear off, and besides, he always woke with a painfully stiff cock, and there was no way he was heading to the co-ed bathroom with that poking out of his shorts.
He opened his phone, and began browsing for some viewing material that might help satisfy his morning urge. He was half-asleep still, and as he scrolled through the endless list of thumbnails, one caught his eye. It was a perfectly round, creamy white ass -- smooth and unblemished, reminiscent of a Renaissance painting, cheeks slightly spread to afford a tiny glimpse of a tight pink pussy.
He clicked it, and the picture came to life; that gorgeous ass bouncing up and down as its owner twerked, her ponytail bouncing along with it. As her cheeks moved, they spread ever so slightly, giving him flashes of her pussy and asshole, making his cock throb. He began massaging his cock as he watched, imagining that round ass pressed against his face, tasting the wetness of her pussy, breathing in her natural scent as he probed her holes with his tongue...
Jack could feel himself building to orgasm watching the ass clap on his screen. Two pale white, perfectly manicured hands reached around those beautifully smooth cheeks and pulled them apart, proudly displaying every inch of herself to the camera. Her asshole puckered once, twice, and then blasted a huge, long fart that rang loudly out of his phone's speaker. Cum exploded from his cock, his head flew back onto his pillow as he bit his lip with the force of it. It splattered all over his bare chest, and as he lay there, breathing heavily, gently pumping his cock for the last ounces of pleasure, he was vaguely aware that he could still hear farts through his phone speaker.
The headiness of his powerful orgasm began to wear off, and he reached for his phone to stop the video, on which the girl was still twerking, letting rip as her cheeks clapped. As he picked it up, though, he froze. On screen, shaking her ass, squeezing out violent farts and winking at the camera, was his sister. Despite his shock, his dick was already twitching again in excitement.
Sadie had always been beautiful. Growing up, they'd been as close as siblings could be; being only a year apart in age meant that they had always been best friends, and while Jack knew that his sister was attractive, he'd never been attracted to her.
Now that they'd entered college, Sadie had undoubtedly begun to cut a curvier figure. With a naturally skinny waist and large hips, Sadie had the sort of hourglass silhouette that made all the girls jealous and all the boys crazy, and her shapely ass had always been the focus of Jack's friends' attention.
While her body might have changed, her face hadn't. Sadie still had the same huge, dark eyes that she'd always had, and her long, brown hair was always beautifully straight and meticulously brushed. Even knowing that everyone around him considered Sadie to be the sexiest girl they knew, Jack had always seen her as his innocent sister, and never anything more.
That day in his dorm room, though, had been the beginning of Jack's biggest fetish - and also the beginning of his attraction to Sadie.
He'd missed her a lot when she'd left to go to college, and he felt a little lost at home without her. That last year at home for him, he'd looked forward to her visits, and now he couldn't wait to go home for the holidays to see her -- except after encountering her videos online, he found himself looking forward to it for all the wrong reasons.
Living alongside her again wasn't easy. Jack constantly caught himself staring at her ass, fantasizing about what she did when she was alone in her room, sniffing the air around her, and every time he'd have to excuse himself due to his growing erection, head to his room and watch one of her videos. It was awkward for him, but she seemed none the wiser.
That was, she did -- right up until she caught him. That morning, they'd been watching TV, and Sadie had let out a huge fart on the other side of the living room. Feeling his cock twinge with excitement, he'd had to quietly excuse himself. Not ten minutes later he was sat on his bed, his laptop next to him playing one of her videos, with his cock in his hand. Thinking she was safely downstairs, he'd not bothered to lock his bedroom door, and Sadie had burst in to ask him if he wanted to play video games. Seeing what he was doing -- and, more importantly, what was on his screen -- she turned bright red and ran out of the room.
After a couple of quiet, painfully awkward days of avoiding one another, Sadie had knocked at his door. She told him that she didn't want them to feel awkward around one another and had an idea for how to resolve the problem. When Jack hadn't known what to say, she told him that their parents were going out at the weekend, and they'd be able to continue the conversation properly then.
~
"So," Sadie said as the pair watched their parents pull out of the driveway, "you ready to talk about it?"
Jack blushed, still mortified that his sister had caught him masturbating over her videos, still painfully aware that the girl he grew up with had now seen his dick, in all its glory, rock-hard for her. "I guess," he replied.
Collapsing onto the sofa, Sadie began chewing her nails, as she always had when she was nervous.
"I started making videos just after I went to college," she blurted out. "A girl I knew was doing it, and she was making heaps of cash from horny dudes on the internet, so I figured I'd earn some spending money, you know?" She looked at him anxiously.
Jack, lost for words, just nodded his understanding. Sadie relaxed a little.
"Anyway, I did a couple, and this guy got in touch and asked me for a custom video. I figured he'd just want me to say his name a couple of times, maybe flash my feet or something, but he asked if I could fart into the camera for him." She was staring off into space, absently poking at a hole in her jeans. "I thought it was weird, but he was offering like a crazy amount of cash just for, like, a minute-long video. I thought 'why not, easy money', right?"
"Right," Jack said carefully. He didn't want to give anything away -- he was still a little ashamed that he'd developed the fetish at all.
"Well, I really liked it. The thought of farting on a guy's face, of him being desperate for my bodily functions, it's kinda... hot. Y'know?" She looked him dead in the eye, and he realized that she was asking more than just the question she'd spoken out loud.
"Yeah, I get you," Jack said, not daring to meet her gaze.