A 20 years old young man with raging hormones and a lot of fantasies

Jake had always been kind of unpopular, he had friends alright but had never gotten into any kind of relationship with anyone. He had quite the libido, though, so he spent a good portion of his teenage years on a lot of different kind of porn and that habit had stuck to this day, so much so that he was actually suffering from a mild porn addiction and had developed some fetishes already.

He was sexually attracted to almost every person that was at least a little bit pretty or handsome, no matter their gender. He had fetishes about **** (his three sisters being absolute smokeshows didn't help with that one), about cum play, penis worship, penis and balls smells, taking a dom role, taking a sub role, pregnancy and many others.

So it's very natural that as soon as that System appeared, a few seconds after a had chosen option D, he got impatient to try and look for things to help him live some of his fantasies. He looked at the screen that displayed a message.

Hello dear user #763554748 Jake Thompson and congratulation on your unlocking of the System !

You've been gifted an entry prize of 1000 points

You'll find that the System is very easy to navigate through if you have questions, just think about them and it should come as natural to you how to make it so the system displays an answer, we're sure you already know what we're talking about.

Your display menu is hidden from anyone, only you can see it and you can't talk about it to anyone, even by accident or ****, words would come out censored of your mouth. The edits you make with the system will be rationalized by other people, they will most likely believe what you changed had always been like that, even if they witness the change in real time, modifying their memories as minimally as possible to completely wipe out any inconsistency.

These are the default settings and can be changed at any point in the options.

Enjoy the System !

Jake was so excited about all of this his mind was all over the place and he couldn't focus on what he wanted to do first.

The screen displayed menus and categories as to allow him to structure his thoughts. He went to the "Special powers and body modifications" category. He looked at different perk titles, some were very explanatory, some more obscure. One in particular grabbed his attention : "Cum Warlock : magic semen". He stopped and looked further into it.

Cum Warlock : magic semen

Add three properties to your semen :
Mild aphrodisiac effect
Mild hypnotic effect
Mild addictive effect

800 points to unlock
1000 points to unlock effect strength slider for each characteristic

Jake's eyes opened wide as he was reading this. This could make him fullfill a lot of his most perverse fantasies. He pried further into it and learnt that the mild hypnotic effect was actually just about making someone liking him a bit more over time each time there was contact with his semen.
In order to activate the effect, ingestion, or any kind of internal ejaculation gave the best results but the smell of his cum or simple skin contact also worked, albeit in a reduced manner.

That's so cool, I need this, I can't wait, Jake thought, excited like he had never been before. He purchased the perk, he now had 200 points left and he would need much more before being able to even change the "Mild" strength of the effects to "Medium" or more.

He spent the rest of the period looking for some other things that would cost him 200 points or less but it was always just short of being worth it in his opinion, plus he was afraid of spending too much too quickly and regretting it later. Instead, he started to look at the quests. He spotted one almost instantly: "Do something taboo with your sister", the reward was 500 points. Ok, yes, that's the one I want. It doesn't specify which sister, though... Oh whatever, it probably works with any one of them. He was getting excited again.

On this day, Jake went home immediately after the end of the classes, no chatting with friends, no club activities, he wanted to get home as early as he could, his reasons were twofold: being able to jerk off in peace and devise a plan.

The house was silent, no one was home, as expected. Jake's two little sisters, Lily and Emmie, were in their classes and wouldn't be home for the next two hours, at least. His big sister Hannah though, could be here sooner, he had to be quick.

Lily was the youngest of the family, just 18 years old. Emmie was a year older. Lily was a gorgeous petite blonde with a small frame and long hair. She had one of the cutest face Jake had ever seen, small nose, puppy eyes and full lips.
Emmie was taller though still a bit shorter than Jake. She was a buxom brunette and often taunted Lily about her breast size. Lily was in her senior year at highschool and Emmie had started to take classes at the same university Jake and Hannah attended. The two little sisters would always spend so much time chatting after class, or going out with their boyfriends, they were never home early...

Jake went to his room and grabbed one of his empty flasks from a science set he had gotten as a christmas gift years ago. He booted up some porn and started to jerk off. Jake did his best to collect as much as he could inside the flask. He looked at what he had gathered, it was a good amount, he hadn't orgasmed for a week at that point as he had been too busy and this whole thing with the System had gotten him as horny as ever on that day, hence the important volume.

Now, what do I do with that? He thought. They need to ingest it, hmm? Let's see in the kitchen. Jake went downstairs to the kitchen and opened the fridge, there was a bottle of soda, almost full. Let's try that, I'll put some of it in there. He poured half of his flask's contents inside the soda bottle and tried to stir it gently not to degas the sparkling liquid. Ok, looks good, I'll just have to remember not drinking from this one.

As he was putting the bottle back in the fridge, a new idea came to him. The System said that just the smell of it would work. Even though the effects were nerfed, the idea he just had was low effort and low risk. He went back upstairs and into his little sisters' shared room. They always had that electric perfume diffuser on, and, sure enough, it was plugged in. Jake took it to the bathroom, poured some of the perfume inside it down the sink and replaced it by what he had left in his cum flask, he went back to plug it back in and as he was coming out of Lily and Emmie's room, he heard the front door open. It had to be Hannah so Jake went downstairs to greet her.

Hannah was a 21 years old tomboy. She was as tall as Jake, 5'10", she had some muscles but still very feminine curves. Huge breasts, thick thighs, nice ass... She spent a lot of her free time in the sports and health center of the campus which offered various services. She was using the tanning capsule on a regular basis which explained her skin tone was a bit darker than Jake's. She also exercised quite frequently and was actually just back from a particularly intense session, dressed in her sport clothes still, boyshorts, trainers and a thight bralette that showed of her toned midriff, the faintest tracing of abs was starting to become visible, a testament to her dedication.

Jake was admiring her as she was closing the front door. She turned as she heard him walking, "Hi, Jake !" she exclaimed as she saw him "Hi sis !" he replied, smiling, "How was your day?".
They made small talk as he followed her to the kitchen. "Phew, I'm parched, that tiny bottle I bring to the gym really isn't big enough and there's no way I'm filling it up with the nasty tap water we have in this city..." she opened the fridge and took the bottle of soda.

Jake's heart rate accelerated as he saw her down a good quarter of the bottle in a few seconds. "Mhmm, this has a weird taste" Hannah remarked, making Jake's heart beat even faster. "Really? Is there something wrong with it?" he asked, nervously, sweating, trying to act like it was a small concern. "Nah, I don't think so, it's mild and to be fair, it's not that bad" and as she said that, she took another couple gulps before storing the soda back in the fridge. Jake observed her intently, looking for any kind of change, but she just smiled at him and left the kitchen saying she was going to take a shower.

Damn, is it even working or are the effects that mild? Or maybe it was too diluted? Or perhaps she needs to ingest much more than that? Jake was wondering. Let's see if I can get more out. And with that, he went back to his room and started masturbating to the mental picture of his sister taking a shower as he was listening to the water run in the bathroom two rooms away from his. He had just done it less than half an hour ago so he was feeling a bit sore at first but the image of his sister's curvy body, her tan lines glistening under the shower got him back at full mast in no time.

It didn't take him too long to reach his climax and he managed to collect another decent load, while still obviously smaller than the first one.

After having poured it all back in the soda bottle, he went back to his room and tried to play some video games to take his mind off things while waiting to see the results on Hannah and for Emmie and Lily to get back home. He managed to forget about all of it for long enough not to notice Hannah was taking a little bit more time than usual in the shower.

Later that evening, as the four of them were eating dinner, Jake couldn't stop observing Hannah. She doesn't seem any different than usual, he thought. The tainted soda bottle was on the table and his three sisters had already drank at least a glass of it each, the idea of which had Jake rock hard under the table.
"Are mom and dad coming back home this week?" asked Hannah, "I don't dislike cooking for us all but I miss mom's dishes..."

Miss and Mister Thompson, Jake's parents, were quite the workaholics and were away most of the time since Lily, the youngest, had turned sixteen, two years ago. They were able to afford a big house thanks to it, however, and even though they didn't see them as often as they wanted, the four siblings were grateful for their parents and loved them dearly, which was completely reciprocated.

"No, or at least not before saturday night, as mom told me on the phone at lunch today" Lily answered. Her brother and two sisters got the same bitter smile. "Yeah, so probably not before next week, then. No way they come back on saturday..." Jake dropped, with a slightly jaded tone. No one responded but they all acquiesced, Hannah letting out a faint sigh.

The rest of the dinner went as normally as it could go, the conversations having lightened back up. Jake couldn't notice a single change in any of his sisters' behavior. He decided to try something, at the end of the dinner, he got up and kissed Hannah on the cheek, just a quick smack, "thanks for the dinner, sis !" he exclaimed, cheerily, as he brought his empty plate to the dishwasher. It was absolutely not something unusual for him to do but he noticed that Hannah was blushing and gently caressing the area he had just kissed absentmindedly. Lily and Emmie were too engrossed in a conversation about their respective boyfriends to notice anything.

After dinner, as Jake had gottent back to his room, he was thinking. Damn, I'm still so horny... Everytime one of them brought that liquid to their lips, my cock throbbed... I wonder what Hannah is doing, maybe I can spend some time with her, chatting, maybe we can wtach a movie together tonight or something, she won't say no to that... On that thought, he got up and walked towards her bedroom door. He was about to knock when he heard her on the phone.

She was probably talking to her boyfriend, Jeremy. Jeremy was a year older than her and was also a student. They met at the gym where he worked part time as a trainer. He was tall, ripped and super handsome and had Jake jealous of Hannah. Jake couldn't quite make out what she was talking about but the conversation didn't last long. When Jake couldn't hear anything anymore, he knocked. "Come in !" Hannah's voice responded.

She was on her bed, her phone still in hand. Jake looked at it, then in he reyes. "How is Jeremy?" he asked. Hannah smiled, "He's fine. You guessed I was just on the phone with him, huh? Well you're correct. I called him because... I... Wanted to see him tonight..." She paused. "But, yeah, no he's busy." She looked a bit disappointed. "Aww, sis... What a bad boyfriend... His girl needed him and he couldn't come? She'll get stolen from him if he continues like that..." Jake said on a playful tone, bringing Hannah's smile back instantly "Hey, stop teasing me. By the way,did you need something?" She asked. "No, I just wanted to spend some tie with my beloved big sister. Since you're not Jeremy-ing tonight, wanna watch a movie or something?" Jake answered, nonchalantly. "Sure thing !"

That night went like any other night in a house with four siblings. Nothing happened. During the rest of the week, Jake tried to take note of every little change he could witness. Emmie and Lily hadn't realized anything about the smell in their room. Jake masturbated a lot and spiked various drinks and foods. He noticed his sisters were a tad bit more shy around him, were taking longer showers and needed their respective boyfriends more often. If he wanted something bigger to happen, he had to take matters in his own hands.