Max could be described as a nerd. He wore glasses, fairly skinny, always had straight A's throughout high school and most of college, and spent most of his time at his computer. At 23, he had graduated college and was a year into working hybrid at a medium sized company which specialized in AI. He still lived at home to save on rent, but it didn't bother him much. His parents spent long hours working at their restaurant, his two older sisters, Ali and Hanna, had already moved out, which just left his younger sister Karin. She was 19, a freshman at the local state college, only a couple hours away.
It was the start of summer and Max had to make the drive over to her college to help her move out. She was a decent student and enjoyed her first year, but was happy to get back home and enjoy her summer break. Karin had a lot of her firsts in her freshman year, most of them involving her first boyfriend and his friends, but they had broken up halfway through the year. She was coming home single and without any action for a while, eager to see if any of her old hookups were still around.
The campus hadn't changed much since Max had graduated a year ago. He'd spent most of his time in his apartment anyways, either studying or gaming, leaving for the occasional party or to catch up with his high school friends. He finally parked near his sister's dorm and sent her a quick text before heading up to her room. Max knocked, waiting a little before knocking again since he didn't hear a response. The door swung open revealing Karin in a white towel, her black hair falling in wet strands past her shoulder. She smiled once she saw Max.
"Hey Max! Sorry, I just wanted to take a last minute shower before I get in the car for a couple hours"
"No problem," he answered, trying his best to keep his eyes on her face. She had certainly grown during her first year at college, her towel not doing much to hide it. Max thought that she might've gained the infamous freshman 15, but certainly not in her belly.
"Come on in, I just have a couple more things to pack and then we can get out of here. This is my roommate Bea by the way"
Karin turned around and walked back into her room, pointing at a girl who was still in bed on the left side of the room. She was half covered by her blanket and was browsing on her phone. From his angle, Max had a great view of her cleavage, Bea's massive boobs were barely contained by her white tank top.
"Nice to meet you," Max said, just getting a grunt in return.
Karin looked back at him apologetically, still stuffing the last of her clothes into a suitcase. Max stole a couple glances toward his sister when he thought she wasn't looking, her hourglass figure showing itself through her towel as she moved around.
Max had always found her attractive, even when she had no boobs or butt. He thought she had the prettiest face and all of his friends agreed with him, always trying to go over to his house to catch a glimpse of her. Her transformation at college had made her even more beautiful in his eyes.
"That's about it! Can you grab this suitcase and I'll meet you in the car once I've changed?"
He nodded, grabbing the suitcase, wishing he could stay and watch.
"I'm just in the parking lot over on the right, same car as always"
He sat in the front, watching the other students walk on by. He spotted a pair of girls heading to the gym, clad in only sports bras and biker shorts. He was already feeling aroused by both his sister and her roommate, wishing he could be at home in his room, lotion and tissue by his desk.
He spotted his sister coming out the front and went to help her with the rest of her bags. She was dressed in what looked like a black bodysuit, the fabric disappearing into her jean shorts. The front cut was fairly deep, showing off her cleavage. He grabbed a bottle in the back and handed it to her once he got in the car.
"Thought you'd like this," he said, starting the engine.
"I've never seen this before, thanks Max," she said, giving him a quick hug.
Karin was always eager to try new things. Whenever Max saw something he thought she'd like, he'd get it for her. She was constantly picking up new hobbies, or joining new clubs at school. Her latest phase was fashion, Max noticing that she was posting a lot more pictures on her Instagram with a lot more new clothes. Not that he minded; those pictures were often the fuel of his fantasies when he was alone in his bedroom.
The two siblings spent the drive catching up, mostly Karin talking since Max didn't have many stories from work. She talked about her classes, dorm life, and parties she went to, leaving out a lot of the wilder things she did. By the time they knew it, they were already home. Their parents were still at the restaurant and wouldn't be back till late. He brought her suitcases up to her room and retreated back to his. He had spend the ride wondering what she really was up to at the frat parties, knowing her penchant for new experiences.
Max locked his door and booted up his computer, opening up a browser to an account he had spent a while on. Working at his AI company had made him curious to all the new uses for it. He had seen people using it to generate fake backgrounds for their pictures, writing stories, and even using it on videos. Max himself didn't work on any of the actual projects, instead doing administrative work, but he had seen its capabilities and even got some of his seniors to give him pointers. It started innocently, just taking the new pictures from his sister's social media and turning them into a cartoony style. He posted the photos for fun, just to get them out there, not thinking it would get so much attention.
"Hot!"
"Moremoremore"
"What I would do to her..."
These types of comments could be seen under a lot of his photos, his collection growing every day. He had tried to branch off and use photos of celebrities or other women, but his followers kept demanding more of his sister. He eventually started just posting Karin and even took the account a step further, using AI to put on new outfits on her. He'd even gained enough followers to start a subscription system where people would pay to get early access to the pictures and some subscriber only ones too. He hadn't realize so many would even be interested in paying for non-nude pictures, but the cash flowing in kept him happy. He had of course experimented with creating more racy pictures with her and even some nude, but never had the gall to post them, feeling like that was a line he shouldn't cross. Max saved half of what he earned so far to give to Karin, but was hesitant to as she would ask where it came from. Instead he used some of the money to buy her things, assuring her it was alright as he got a bonus at work, and kept the rest in his desk.
Max unzipped his pants, fishing out his cock with one hand and grabbing lotion with the other. He pulled up some porn but left it on his second monitor. He started going through his account, absentmindedly scrolling while really thinking about Karin in a towel and her roommate Bea. He was halfway through his fantasy, thinking about Karin dropping her towel and Bea joining in when he began to feel the urge to cum. He grabbed a tissue, shooting sperm into it a few seconds later. He closed out the porn tab when he heard Karin shout from downstairs. He cleaned up and went downstairs, yelling back.
-------------------------------------------------
After dinner, Max lost rock paper scissors so he finished up the dishes. Walking back upstairs, he saw his room door open and Karin sitting at his desk. He could see she was scrolling through his account. Max could feel himself start to get red and was thinking up dozens of excuses when his sister turned towards him with a glint in her eyes.
"Wow Max, this is pretty cool! I knew you did AI stuff at work but I didn't think you could do stuff like this. How cool do I look?"
Max didn't expect this reaction but tried to go along with it.
"This stuff is just practice for work or something right? But I do see you posted a lot of me..." she trailed off.
"A-actually, I just posted it as a test but it got a lot more attention," he stammered out. Max was flustered but managed to open up his drawer where he kept the cash from the account.
"Here, it actually did really well which is why I kept posting," he said handing her a decent wad of cash.
She looked down, the flimsy excuse already forgotten.
"Oh! Wow this is a lot"
