It was the summer after my senior year in high school. Since we were all going off to college in a few months, my close group of friends tried to spend as much time together as possible.
Our 'homebase' was our friend *Amber's house... her parents were very wealthy and her house was huge... most importantly, her parents were always gone; so you can imagine that worked out nicely for a bunch of teenagers!
Amber had a younger, 13 year old sister named *Katie. And even just at 13, you could already tell Katie was going to grow up to be a beautiful girl.
When all of our friends would hang out at Amber's house, Katie was rarely around or when she was, locked herself in her room, having no interest in the goings-on of soon-to-be-college kids.
Well, one afternoon, everyone had been swimming in Amber's pool. I was tired after a few hours and went inside to shower off the pool-water. The house was otherwise empty with everyone being outside, and I used Amber and Katie's shared bathroom to shower.
Afterward, I walked from the bathroom toward Amber's room, where my dry clothes were being kept and I began to pass by Katie's room on the way. Her door was wide open and she was gone. Being nosey and curious, I walked into her room (wearing only a towel) and began to peek around at all her stuff. As a typical young teenager does, she had plenty of photos of herself and her friends taped to the walls everywhere. Looking at her, I couldn't believe how absolutely gorgeous she was, though still under-developed as most girls her age were. I could only imagine how she would fill out as a woman...
Well, thinking these thoughts, my cock began to grow hard and in turn, the towel around my waist started to rise in the front. My search inevitably lead to her dresser.... And I knew what I wanted to see...
...And opening the second drawer from the bottom, I found them: Katie's panties. Though I am no prude, especially at my age then, I simply could not believe what kind of panties Katie had (or for that matter, what her parents allowed her to have). Now, this was the time before thongs and g-strings went mainstream, so she didn't have any of those.... but what she had was as close as could be! Narrow cut backs that I surmised would only cover 1/2 of her butt, thin strings connecting the back to the front, low-cut and low-rise tiny triangles of silk and satin that made up the front.... Katie was a 13 year old, not a stripper! And to think, the sizes these panties were, were intended for kids! They were not adult or teenagers! I can't believe a company would even make these for children! I was expecting to find full-coverage generic cotton panties with cherries or hearts on them. Instead I found something closer to what her older sister might where on a college-date!
Anyway, I started inspecting her panties one at a time; looking carefully at the crotch area for stained or dried remnants of juices or otherwise. I took turns sniffing them, too. Some smelled like the familiar, sour-melon musk of a girl's vagina, others had no smell at all. I became so turned on at the thought that these very panties I held in my hand cover the sweet, young bits of 13 year old beautiful girl who cannot possibly predict how she will grow up to conquer men and break hearts.... but here I had a keep-sake of that future woman, when she was just in her beginning stages.
Well, that was enough for my to take action. I plucked out a particular nice pair of blue satin panties, with thin ribbed strings connecting the back to the front. While still nice, I could tell they've definitely been worn many times before. I took off my towel and spread out on her bed. I wrapped Katie's panties around my throbbing hard-on, making sure the patch of the material that would cover her vagina covered the head of my cock. I then grabbed a purple pair of cotton panties which had dried bits of juices stuck to the crotch, and put them over my nose and face...
...Then, I proceeded to jack off. Gripping the satin that was wrapped around my cock, while inhaling the remnant order on the crotch of the panties that lay on my face, I wasn't masturbating to the idea or fantasy of having sex with Katie. She was only 13 years old and that would be wrong to take advantage of a girl that young. No, I was masturbating to the idea that I knew how gorgeous and desired Katie would be some day. I knew men would be fighting over her and be practically suicidal when she broke up with them.... I knew that many, many men would be masturbating to the fantasy of having sex with the 'adult-Katie'.... so I guess you could say that I was jacking off to the future... to the future of a soon-to-be beautiful woman, and that I-in a sense- got there first, when she was only 13 and on the brink of discovering the woman she would become.
And with that, I came and came hard... right into the crotch of those sexy satin blue panties that had been wrapped around my dick. After I was done, I unraveled the panties and looked at my gobs of semen sitting in the small triangle of fabric. I thought, 'This is the first time a man's semen has ever touched something of Katie's that is as intimate as the thin barrier that separates her vagina from the rest of her clothes and the world.' I then proceed to rub my semen into the panties, soaking and grinding my fluids into the fabric. Then, I placed them under the rest of her panties at the bottom of the drawer to ensure whenever she would eventually get to them, they would be dry. My hope would be that she would not notice anything unusual as she slipped them on and walk around all day, unaware that she was indirectly having an echo of a sexual encounter with the first of many men that would grow to worship her when she was older.
And with that, I wrapped my towel back around my waist, straightened the sheets on her bed so she wouldn't ever know anyone was there.... and I went back to Amber's room to get dressed. Oh, and I almost forgot, I did keep the purple panties I had been sniffing as I jacked-off as a keepsake of the girl who-would-be Queen of men's hearts.
I was 17 then, and am 30 now. I'm happy to report that Katie DID in fact grow up, fill out, and is now more beautiful than she was ever thought to be. She's pursuing an acting career in Hollywood and I hope she will one day make it, so I can say, if only to myself, that I was there from the beginning.