"What do you mean 'participate fully'?" asked my niece nervously. Her mother looked at her thoughtfully for a moment.

"Are you still a virgin?" she asked. My niece nodded shyly. "Really?"

"Yes. I mean, mostly, I guess. I've kissed a couple of boys."

"That's all?" my sister asked her, dubiously. "There's no need to hide anything now. You've just watched me give your uncle a blow-job and swallow his cum. You can't tell me anything that's going to get me mad now."

"Well," my niece answered slowly, reluctantly, "I haven't gone all the way, but one boy did rub my boobs, and I had my hands on his... you know."

"His cock?"

"Yes, ma'am." My niece was blushing furiously at this point.

"Did he come?" I asked. Despite my misgivings, I found myself transfixed by this conversation. My sister looked at me in a way that made me think she was getting ready to say something, but instead she turned to her daughter.

"Well?" she asked. "Did he?"

"Uhm... no, I don't think so."

"Have you ever seen a boy, or a man, have an orgasm?"

"No, ma'am. I'm not really sure what that means."

"Well, you saw what came out of your uncle's dick while I was sucking him, didn't you?"

"Actually," I interjected, smiling,"she probably didn't. She was kind of busy with her own needs. But she saw some of the clips, right?" I asked, looking at my niece.

My sister looked between my niece and me. "Fine," she said, finally. "Do you want to stay or not? If you stay, you are going to learn all about sex, first hand. You don't have to do anything you don't want to, but I will assume that your uncle or I can do anything unless you specifically say no. You can't watch from the sidelines, though. You'll have to get undressed and join us on the bed."

"Now hold on," I said. "Just because I like watching those videos doesn't mean I want to actually do that stuff, especially with my own niece."

"Bullshit," my sister said, laughing. "Look," she continued, "I was pissed at first, but the truth is watching those clips on your computer turned me on. I never could understand how some guys could like seeing young girls do those things, but seeing it for myself... Well, it's very erotic. Now are you going to tell me that you really don't want the opportunity to do something with a young girl? As long as she's willing, that is."

I looked to her daughter, raising an eyebrow. "Are you willing to join us? As your mother said, you don't have to do anything you don't want to, and if you start getting uncomfortable you can leave at any time." She nodded shyly, and I could already feel my dick stirring again, thoughts of what I'd do to this young girl if given the chance dancing through my head.

Let me take a moment to describe my sister and niece, since I haven't yet done that. My sister removed her blouse and jeans, revealing a body that was once athletic but had started to turn pudgy. She isn't fat by any means, but she was carrying an extra 20 pounds around, now that's she's 35, that she didn't have when we were growing up. That didn't bother me any, as I prefer women a little heavy instead of too thin. As she removed her bra, I reminded myself that this was the first time I'd seen her naked since we were little kids (I was 5, she was 8) taking a bath together.

Her tits were absolutely fantastic. Soft and round, nipples growing larger even as I watched. The areolas were almost perfectly round, and were just the right shade of tan to offset the milky whiteness of her skin. I couldn't help myself; I reached over and cupped one of them, then lowered my head to suck on the nipple, making her gasp. She ran her fingers through my hair for a moment before I straightened up and watched her peel her panties down over her ass, which was just starting to get a little flabby. Again, this did not bother me in the least; I could hardly wait to get my hands on it. Her pussy hair was neatly trimmed, but not shaven or shaped in any way.

Meanwhile, my niece, having decided to stay, also started undressing. She pulled off her t-shirt to reveal two very nice, just-budding breasts. Not quite large enough for a real bra, I thought to myself that she should probably start wearing a training bra soon. I couldn't believe that I hadn't noticed before, but now it was obvious. She took her shorts and panties off, revealing the sweetest looking pussy I think I'd ever seen. The small amount of hair growing there was light and whispy, with just a hint of a tuft at the top of the slit. She was also a little heavy, but her legs were long and firm and her stomache mostly flat. Again, thoughts of what I'd do to this sweet girl (if she'd let me) danced through my head. I longed to caress her tit like I'd just done to her mother, but I hesitated. I guess my sister recognized this, because she said to both of us "We are going to assume that everything is allowed, for all of us, unless someone says 'no', understand?"

I nodded, looking at my niece. She nodded too, still blushing. I was surprised at how readily she had undressed, but now she seemed a little uncomfortable. "Let's get into bed," I suggested, "and see what happens." My sister reached over to me and took my robe off, tossing it on the door hook.

We got in bed, and by some unspoken agreement all three of us faced to the center, cross-legged. Both my sister and my niece had their hands draped in front of their pussies in what was supposed to be a casual position. I was just chuckling to myself about it when I realized I was doing the same thing. Considering one of them had just sucked me off, and the other had watched, it was a little silly.

Finally, sighing, my sister said “Okay, why don’t we watch a couple more of your videos and see if that breaks the ice.” I thought that was an excellent idea, so I got my laptop off the nightstand and started going through my collection to queue up some of my favorites. I’d just come a few minutes earlier, and though I’m still a young man I didn’t want to miss out on an opportunity like this. I wanted to make sure I would be able to get hard again. (As it happened, this did not become an issue at all.)

I started a clip, and we sat back to watch. I was now sitting up beside my sister, my arm draped over her shoulder and my hand playing with her right boob. The nipple was huge, and hard as an eraser, and I was loving it. My niece was sitting beside me, but a little apart from us. I reached over and put my left hand on her thigh, just above the knee, and chuckled when she jumped a little. But she smiled and scooted just a little closer to us, so I left my hand there.

On screen, a young girl was on her knees, looking up at the camera with a “fuck me” look in her eyes. She was giving the camera man a slow, sensuous hand-job and saying something, but as is often the case there was no audio. (And when there is audio, it’s usually Russian or some other language.)

The other two were watching closely, especially my niece. My sister, without looking away, asked “Where do you get these files from?”

“Usenet newsgroups, mostly,” I answered. “They aren’t easy to find, but if you know the right search terms you can run across them.”

“Like what?” she asked.

“Well, generally I do a Google Usenet search for a name of one of the better posters. Sometimes I’ll get lucky and run across his text posts in a particular group, then I’ll check it out with my reader program, which is called Agent. If it’s been a good week or month, I’ll find a bunch of clips like these.”

On screen, the girl was now blowing the guy, but was being kind of tentative. “That’s called a blow-job,” my sister told her daughter. “Most guys really like that. Just ask your uncle.”

“Do you really like that?” she asked me.

“If it’s as good as your mother just did, I love it,” I replied. “In fact, most of the clips I keep are of this type, because it’s what I like most to watch and to do.”

My sister looked at me. “Really? You like that better than fucking?” To her daughter, she said, “Fucking is intercourse.”

“Oh, Mom,” my niece laughed. “Even I know that!” We all laughed. Hey, we were still all a bit nervous.

On screen, the guy has put the camera down behind them so that you can watch him mounting the young girl. Her legs are around his hips as he slides his dick up and down her pussy, giving her clit a good working over. My sister was rubbing her own pussy absent-mindedly, then she turned to me with a look of lust and longing in her eyes. I told her to lay back, then I positioned myself between her legs so that I could start eating her.

She was so fucking wet! As soon as my tongue touched her clit she started shivering and she placed her hands on my head to guide my actions. I reached my hand under her as and started fingering her pussy and butt hole at the same time. I don’t know if she’d ever had anal sex before, but her ass hole was tight and hot, but my finger was slick from her pussy juices. I glanced up at my niece, who was again looking between what was on screen and the live action.

On screen, the guy had finally entered the girl and was slowly fucking her. The girls hands were clenched on the guys back in (what I hope was) pleasure. My niece saw me looking at her (while I was still eating her mom), smiled, and started rubbing her own pussy. I stopped eating to ask her “Is that how you masturbate at home?”

She blushed, but nodded. “Do you ever stick your fingers or anything else in?” I asked. She shook her head no, and her mother said “Enough talk, mister. Go back to work!” and she pushed my head down.

Just as the guy on screen pulled out to come on the girls pussy, my sister started quivering and moaning, pushing my head into her pussy even harder. I started licking furiously, concentrating on her clit, and her moaning got louder. I heard my niece panting as well, but was unable to look at her because my sister wasn’t letting me up for anything. Soon, she squeezed her legs together, clamping my head between her thighs, and started bucking wildly. I pushed my thumb in her pussy, and my finger in her ass hole, as far as they would go. She came hard and loud, then finally let my head go.

I came up, gasping for air but smiling broadly. My niece was transfixed, watching the screen as a girl of about 16 was eating the pussy of another girl, probably 13 or 14 (a different clip). The girl getting eaten didn’t seem to be getting much out of it, but the 16 year-old certainly looked to be enjoying herself.

My niece looked at me and said “Girls do that to each other?”

“Sometimes,” I answered.

“Have you ever done that, Mom?”

“Once or twice, when I was younger,” she replied, smiling. “Would you like to try it?” I nearly choked at that.

“Maybe, we’ll see,” answered my niece. “First, I’d like to do that to him.” Another blow-job clip was on, and she was pointing at my cock as she said it. I looked at my sister, who shrugged, and I turned so that I could put one leg on each side of my niece.

“Okay, but go easy. Make sure you don’t use your teeth, and when I say stop, I mean stop.” I didn’t think she would react well to getting a mouth full of cum on her first blow-job.

My niece watched the screen a bit more, getting an idea of what to do. She reached over and tentatively grabbed my dick, now throbbing, and squeezed it a bit. I was in heaven. When she leaned over and kissed the head of my dick, getting a bit of pre-cum on her lips, I thought I would pass out. Suddenly, she popped about two inches into her mouth, and I nearly blew my load right then and there. Until, as I knew was inevitable, her teeth scraped hard across my glans.

“Ow, shit!” I cried. My niece stopped immediately, looking scared. My dick was already starting to wilt, and my sister, the bitch, was laughing her ass off.

“No teeth!” both my sister, still laughing, and I, almost crying, said together. My sister laid down so that her head was at my crotch, and she put her hand over her daughter’s so that they were both stroking my cock. I was already getting big again, so no harm, no foul.

“Let me show you,” my sister told her. “First, be very gentle with a man’s cock. It’s very sensitive, especially right here,” she said, biting gently just under the head. I jumped a little, but it didn’t hurt as much as it looked like it would. My sister gave me an evil grin, then said to her daughter, “Don’t bite until you have a little better idea what your man wants. Just lick,” she said, demonstrating, “and suck,” again, demonstrating. She held my cock towards my niece, encouraging her to try again.

My niece slowly licked my cock, instinctively starting at the base and slowly working her way up to the head (she’d seen that on one of the clips, so maybe it wasn’t instinctively after all), and when she got to the top she again put the first two inches in her mouth and sucked a little.

“Oh, god!” I moaned. “That is so much better.” My sister pumped my cock gently as her daughter continued to suck, then took it from her and sucked it some more herself. “Go a little deeper if you can, but don’t go to deep or you’ll gag. No guy wants you to puke on him.” My sister was doing a great job of demonstrating exactly what she meant, and my niece was doing an excellent job of following her instructions. Before long, my niece was able to get about four inches in. (I'm not huge, but I do go a respectable eight inches.)

If it hadn’t been for the near bite my niece gave me at first, I surely would have come already. So I guess it was for the best, because now I was enjoying a first: two women (okay, a woman and a child) sucking my cock at the same time. I caught my sister’s eye and motioned for them to slow down, so she gently pulled my cock from my nieces mouth. She nudged her daughter’s chin up, and when she had turned her face to her, she kissed her. I watched, transfixed, as their kiss turned more passionate, and their tongues started playing together.

Although I’d seen similar clips from the internet, nothing could compare to the eroticism of watching my sister and niece engaging in such a kiss. My sister guided her daughter’s hand to her tit, then she reached down to my niece’s pussy and started rubbing her. I rolled over so that I was behind my niece and started playing with her nipples, which were every bit as hard as her mother’s, though of course not as big.

My sister rolled over onto her back and pulled her daughter up between her legs, still kissing her. She pushed her head down, and my niece started sucking on first one, then the other, nipple. I played with myself, but only a little as I didn’t want to come just yet, watching intently. My sister pushed her daughter’s head lower, and my niece kissed down her stomach until she got to the hair line of her mother’s pussy. She looked up, and my sister smiled and nodded, and raised her legs up. My niece bent her head down and started licking her mother’s pussy, trying to mimick what I’d done just moments earlier.

The way she was positioned, my niece's ass was stuck up in the air and I could not resist. I moved behind her (the computer was all but forgotten now, so I set it aside) and started rubbing her slit. She wasn’t as wet as her mother had gotten earlier, but she was buttery and her pussy lips, though not as full as they would be when she grew up (as I would learn from first hand experience), were still puffy and soft. She twitched every time my fingers brushed against her clit, just as her mother was twitching from her tongue work. I stuck the tip of my finger in her tight pussy hole, and she let out a long sigh and stopped licking her mother’s cunt.

I gently worked more of my finger into her tight hole and continued rubbing her little nub, enjoying the effect it was having on her. The whole time my mind was practically screaming “This is your niece! And your sister!” I stretched out beside her and pulled her leg over my head so that I could finally taste this young girl’s virgin pussy. At the same time I could feel first one mouth then the other take my cock into it, with short breaks in between while they, I guessed, kissed.

I didn’t know who was who, but when I stopped licking just long enough to say “I’m going to come” I assumed the mouth that engulfed me was my sister. I came for the second time in half and hour (that’s right, only 30 minutes had passed), and felt my niece tense up as her pussy started clenching and unclenching. Then she started coughing and I knew it was her mouth I’d just come in! It wasn’t what I’d intended, but her mother thought it would be okay since I’d already came once and the second time wouldn’t be as much.