[MF] I jerked off while spying on my stepsister [18F] having sex

This is part 2 of the adventures with my stepsister. Click [here](https://www.reddit.com/r/gonewildstories/comments/h7krnu/mf_how_i_21m_spied_on_my_stepsisters_18f/) to read part 1. Enjoy!

Around one month after I’d spied on my stepsister, Katie, fingering her perfect pussy, she started dating a guy named Thomas.

He was a short nerdy dude, with round glasses and curly hair. Nothing special to be honest. He definitely knew how to dress himself though, to make himself look like a member of a boy band.

The times I had the chance to talk to him, I enjoyed it. We had similar interests and shared our enjoyment for gaming.

I honestly thought they fit together nicely. She seemed happy around him. Even our parents were very fond of him, letting him visit all the time under the excuse of studying.

But let’s get back to myself and my little spying misadventure.

Trust me when I say that for a week straight after the incident, I was so anxious around Katie that one time I physically jumped away when she casually touched my arm. It was embarrassing and I couldn’t stop getting weirded out when I jacked off to the memory of her plunging her slim fingers into her little pink pussy. The more disgusted I was with myself the stranger it felt to stroke my cock imagining her perfect little ass in the air.

I’d basically gone through the whole Kamasutra in my mind at that point. I spilled cum thinking about destroying her wet hole and making her orgasm over and over. Fingering, licking, fucking. Every and all positions.

Her body was so petite and smooth. The image of her skin, slightly tanned and glistening as she pleasured herself intensely made my cock harder than ever before.

I was in a perpetuate state of horny and disgusted with myself and it had to stop.

Thankfully, after around a week of this horny horror, it started to get back to normal. I really needed to focus on uni and she was out of the house often so there was no chances of any awkwardness to ensue. I’d still jack off to the memory of her fingering herself, but not that often and I even got a tinder account to hopefully get myself a one night stand or something. I was really trying to move on.

It weren’t that simple though.

Granted, it did get easier to be around her after some time. We chatted like always before and it seemed like she didn’t notice that anything had happened.

On the other hand though, I started noticing things about Katie. How perfect her peach shaped ass looked in the tight jean shorts she worn often. Or the outline of her small breasts through some white tank-top. It was weird but I was done behaving like a virgin boy and just accepted my sister was super hot.

I justified my horniness in my mind and went on with my life. After all, we weren’t even biological siblings. It didn’t matter, right? Right.

One time, I went to the bathroom after she’d just finished showering and noticed a pair of white panties peaking out in the laundry bin. She had just returned from a long walk and it had been a warm day. They must have been soaked. The temptation. I ALMOST grabbed them and wrapped my cock around them. I know I’d love it but, no, I decided I wasn’t that degenerate.

(Haha, yet).

Anyways, let’s get back to Katie and her new boyfriend.

You see, I always suspected they were doing *other stuff* while pretending to be studying but I didn’t really care. I imagined them fucking once or twice but it wasn’t my thing. I guess I preferred the image of her slender figure all to myself.

One day, my parents were out of the house. They went to visit their friends who lived quite far away. When this happened, they were usually gone for multiple hours and came back at night. Normally, Katie wasn’t supposed to have guests when our parents were not there but she asked me if I’d tell if she invited Thomas and, because I was cool like that, I said no, of course not.

When he arrived, all three of us chatted for a bit and decided on ordering pizzas for dinner. I asked what their plans were for the evening. Katie immediately answered there was some new show she wanted them to watch. Netflix and chill, I thought to myself but didn’t say. Instead, I just told them ‘no weird stuff’ and we all laughed.

We were both in our rooms, me playing video games with my headphones on and her and Thomas in her room, next door, watching some kinda show, apparently.

After some time, I heard a knock on my door. It was Katie with my pizza in her hands. I guess I didn’t hear the door bell with my headset on. I thanked her and she said no worries. She lingered a bit and I noticed her looking at me kinda intensely. I looked back and said asked if she needed anything. She shrugged and mumbled something about me listening to loud music. I had no one what she was on about but she left my room and there was no point asking again.

It was around forty minutes after when I needed to go pee. I took my headset off, stood up and immediately paused in my steps. I could hear an audible bed creaking sound. It wasn’t loud and it didn’t happen often but it was definitely there. I stood still for solid thirty seconds, making sure to make no noise myself, and listened closely.

Either they were having some kinda pillow fight or Thomas was fucking my sister on her bed.

Now it all made sense, she wanted to make sure I was listening to music when she came in my room earlier. She clearly assumed it cause I didn’t hear the door bell.

The creaks stopped for a bit and I decided to go ahead and head to the bathroom. Again, I was making sure I was as quiet as I could. I felt like a ninja.

I managed to open the door to my room without any noise and stepped out on the corridor. That was when I heard a muffled moan coming from next door.

Pissing entirely forgotten, I tiptoed towards my sister’s room and stood next to the door, heart pounding and dick throbbing hard all ready. I had no underwear on so the black joggers I wore spotted a massive tent in the front. From this close, I could clearly make out Katie’s moans. They didn’t happen constantly and were audibly muffled when they did so I was sure she had something blocking her mouth. Obviously not wanting her brother to notice she was having sex.

I racked my brain to find a way to spy on them, to see Katie’s body being fucked. But there was nothing. The door was solid white, no glass, no keyhole, nothing.

I rested my back against the wall and put a hand in my joggers. I jerked off then and there, rough carpet under my bare feet and cold stone pressing against my back. I pumped my thick cock relentlessly. Eyes closed, I imagined Katie in the same position as when I caught her masturbating. Her round ass raised in the hair, exposing her perfect butt hole and the pink, tight flower that was her smooth pussy. With the moans and the bed-moving sounds it was extremely easy to imagine myself behind her, sticking my hard dick inside her. It was me making her moan, destroying her little pussy. I imagined myself pushing her head into the pillows, grabbing her hair and making her stay in this position for me. Ass up – face down.

My hand glided over my cock with ease. I could feel I was getting closer and closer. I wanted to spill my seed in her pussy so bad. I wanted to be the one enjoying the warm wetness for myself. Oh god, I could almost feel her perfect hole swallowing my dick deeper and deeper as I plunged it in.

I cummed all over my hand and pants, making a big mess. Fortunately, I managed to stay quiet through the orgasm and I stood still for another half a minute or so, listening in to the sex noises even after the bliss had passed.

As my mind cleared, I glued myself off the wall and tiptoed to the bathroom, the carpeted floor proved ideal for ninja work.

This time, there was no shame in me as I washed myself off. I didn’t care any more. The period of being embarrassed with myself for being horny for my sister was over.

Quietly, I returned to my room. But I wasn’t going to leave them have their fun like that, oh no. I made sure to close the door loudly, so they would hear in the room next door. I stood still for a bit and all I heard was perfect silence. Imagining them perfectly sill, his dick shrivelling down still inside her, as they looked at each other in panic, I almost laughed out loud but decided not to be a jackass and just returned to my PC.

My pizza was all cold by now but I didn’t really care. What a great day it had been.

^(Guys, thank you so much for leaving such nice comments under the first part! Thank you for the compliments in the pm’s as well! Feel free to send them in, I love reading your guys’ thoughts! See ya in the next part!)

Source: reddit.com/r/gonewildstories/comments/h87n7e/mf_i_jerked_off_while_spying_on_my_stepsister_18f