This happened seven years ago, but remains one of my most masturbated memories.
Jean and I had flirted shamelessly with each other for a good three or four years now. We worked together at a local mall's food court. We were both interested in each other, but never got together, I'm not sure why; maybe we didn't want to ruin our mutual attraction by complicating it with dating. Of course, we were both often dating someone and didn't end up single at the same time very often.
Her current boyfriend (at the time, anyway) was a big lug of a stupid brute and I thought she could do better. They were sexually active; he always wanted oral sex, but would never return the favor. She would complain about that to me pretty often. I told her I'd do it. I'm sure she thought I was teasing or flirting, but I was being honest. We'd talk about sex a lot, but how many co-ed fast food workers in their early twenties don't? It grew to the point where we'd brush up against each other and touch body parts that would be off limits to most people, by accident of course (heh heh).
Well, one weekend her parents left her home alone. So we had a party, naturally. A boy-girl sleepover, no less! Nothing happened that night, but the next day, oh my! She took that day off, knowing there'd be a big mess to clean before her parents got back home. I worked that day, but went over to her house afterwards, expecting a group there to help clean. Well, a few people had come and gone but when I got there I was the only one. She'd finished by that time anyway. So we sat and talked for a while, and then she made a suggestion.
She'd told me about some of her porn tapes before, she and Tom (the stupid boyfriend) had a modest collection. She wondered if I'd like to see one in particular that, I guess, was her favorite. I agreed. I'd never watched porn with a girl before (well, not with anyone, actually). She put it in (the VCR, I mean) and we watched for a little while. I was a porn freak for a few years now, and to watch one and not masturbate was wierd, and I said so. She said that maybe I should. I was pleasantly surprised, but not shocked. I was half-expecting this.
So, down went my zipper and I started stroking. My penis was a little nervous, so it didn't get hard very fast. Now Jean had brushed her knuckles, thighs, and butt against it, she'd even outright rubbed her palm against it once, but she'd never seen my penis before. It seemed unreal, dreamlike. But there I was. I kept my pants on, just undid my fly, but hitched my underpants down as far as I could so that all my modestly-proportioned equipment could stand out into the cool living room air. She didn't expose any body parts, but slid her hand into her pants, and that's how it went for the rest of the movie. I really didn't see any of it, I kept watching the knuckle shaped lump moving beneath her pants.
Once in a while, I'd hear a juicy squishing sound, that was exciting. She kept talking, babbling almost, but I really did enjoy hearing her voice. Her eyes would flit briefly to mine while she talked, or watch the movie for a little while, but most of the time, they stayed pointed at my stroking hand. I was close to cumming for a long time, but I tried my best to draw it out. It paid off, because when I finally did allow myself to cum, I gave her a magnificent display. I had two days worth of semen saved up (quite a feat back then) and I shot almost the farthest I'd ever shot. It was a geyser straight up into the air. She didn't cum, but wore a huge ear-to-ear smile. We never got another chance to do anything more, but were as close as ever afterwards.
We're both married now, she to that boyfriend and unfortunately we have fallen out of touch.