This is a work of fiction. All persons are 18 or older.
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I've always been the designated technical guy in the family, the one who shows everyone else how to work things, the one who backs up everyone's photos and data, sets up the Internet and keeps it running, etc. I guess my family has more of an aversion to that sort of stuff than I do, and I got pretty good at it. I don't consider it fun, just necessary.
Anyway, one Saturday I found myself without a pen, so I went to my sister Jenny's room to find an extra one. We usually split the new packs of pens we buy, so this wasn't an unusual thing for either of us to do.
There was only one half-used pen in the pen holder, so I opened the drawer of her desk to search for an unused pen. I found the pen, but I also noticed a Post-It sheet with what looked like Jenny's computer username and password written on it.
Exasperated at this amateur move, I resolved to lecture Jenny on the idiocy of doing such a thing. Any of her friends could swipe her password and I don't know that I trusted all of them that much. I imagined Jenny's irritation over technical things and decided I needed to verify this was really her computer login info before I started lecturing her about doing something so dumb, so I tried to log into her computer and, sure enough, it worked.
That's when I got the shock of my life. There was an open window with very large thumbnail images in it. The photos were selfies of nude girls! Most looked like they were taken with a webcam, judging from the aspect ratio, but some were clearly taken with a phone. I looked at the number of files at the bottom of the window and there were a lot in this folder. I could only see a handful of them. I looked at them for a few seconds, and my stomach did a backflip. The photos were of my sister! I recognized the room I was standing in, her room, in the background of most of the photos. And I recognized Jenny.
Jenny was pretty and reasonably fit. That was obvious to me as well as anyone else who ever met her. Jenny usually wore her long brown hair in a ponytail, and she almost never wore makeup; she just didn't need any.
Most of the photos were pretty tame, even though she was naked in every one of them. She was usually just standing there, with her side or back facing the camera, though I did see one where she stood facing the camera. One of the photos wasn't taken in this room; it was taken in our bathtub. Jenny was sitting naked in the tub, legs spread, and the tap water was gushing over her pussy!
And then there was The Photo. It was the most amazing photo I had ever seen. It showed her half sitting, half laying in the plush chair under her window, completely naked, legs spread and bent at the knees, pulling one outer pussy lip aside with one hand and rubbing her clit with the other! She was looking intently at her very wet sex. Her toes were curled. The act was so private, so intimate, so sexy, so erotic, and she looked absolutely beautiful. My cock was harder than it ever had been.
I'm a fairly responsible, conscientious person. I knew I wasn't going to scroll through the rest of the photos, even though I was tempted, because I knew that would be an invasion of privacy, and I respected my sister. But seeing my pretty sister doing something so sexual excited me so much, I did do something I really shouldn't have done. I opened the photo of Jenny masturbating, maximized the photo to the largest size possible, pulled my gym shorts down, sat on the same chair shown in the photo and jacked off until I came. I knew it was wrong but I rationalized that I had already seen the photo accidentally, so it wasn't really so bad. The human brain is capable of some truly acrobatic bullshit.
I cleaned myself up, closed the photo and logged out of the computer after I finished my depraved act, and resolved to have a talk with Jenny about computer security. She didn't need anyone else finding this stuff again, including me.
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Later that day when Jenny came home, I tried to have the talk I promised myself I would have with her so we could secure those photos and keep them private. Her door was open so I just walked to her door and started talking, wondering just what I would say and dreading the uncomfortable nature of having to talk about what I stumbled across. I figured I would leave out the part about me masturbating to her photo; she didn't need to know that, and I hoped I could forget about it, though I doubted I ever would. How could I?
"Hey Jenny, you got a minute or two?"
Her reply was friendly enough. "Yeah, I suppose."
"You need to learn about how to keep your computer more secure," I began.
"No I don't, that's your job, I'm no computer nerd," she retorted. "I don't have anything to hide. I'm just a regular girl; no one wants whatever's on my computer."
"You'd be surprised what's on most ordinary people's computers, how easy it is for someone to get a hold of it, and how profitable it is to have," I explained. "I can show you how to protect your data from prying eyes. Just let me teach you how; it won't take too long."
"You're paranoid," she rallied. "There's no point in protecting my computer more than it already is. The entire thing is encrypted with a password; my shit is perfectly safe. I'm not going to sit through your nerd lessons."
Jenny always got annoyed about technical things; she had no patience for it. She really was a nice person, normally, so I didn't take offense. But I was desperate. I needed to make sure she protected her photos. Me seeing the few photos I saw was one thing; I would take that secret to my grave. But other people, people who don't love her, they could do her a lot of harm with very little effort if they ran across these photos. I came up with a spur of the moment plan, one that would wake her up to the necessity of protecting her photos without the need for any patience on her part - because she just didn't have any. "What if I can prove to you that you need this bit of training; would you listen to me then?"
"I don't want to hear a lecture about how I need you to turn me into a computer nerd like you. I'm not into that stuff, okay?"
"Okay, no lecture. You'll get your proof tomorrow morning. It won't take more than 5 seconds. All you need to do is start to use your computer. No effort on your part at all."
"If you fuck up my computer, you're going to get it, mister, you hear me?"
