I only get to L.A. once in a blue moon. It had been years since the last time I was on the west coast. Anyway, I was going to be there for a couple of days so, of course, I had to visit my sister. She has lived out there for ages. She is quite a bit older than me and we were never very close. She got married and moved out there while I was still in my early teens. I'll be 25 in a few months. It wasn't that I wanted to see her that much, but she is family so it was kind of an obligation to stop in.

I arrived at my sister's house about 4:30 after I had finished the job I had been sent out to do. It had been arranged that I would spend the night there and catch a plane back to New York the next day. Sis was the only one home when I got there so we were in the kitchen doing a little catching up while she was making dinner.

It came to my mind that she had a kid so I inquired, "Where's that rug rat of yours? Still in school this late?"

I thought my sister was going to split a gut laughing, "Jesus, bro, you are out of touch. My 'rug rat' is a teenager, for heaven's sake. She's probably hanging out with some of her weird friends, but she should be home soon."

My sister's husband came in soon after that and I chatted with him for a while. He's an alright guy and we got along pretty good. My sis had just called us to come to the table when Caitlin burst in. Man, where do teenagers get all that energy? She talked a mile a minute about school and how dumb her teachers were and all the crazy things her friends had done that day and on and on. I had to admit she is a really cute kid and she seemed to know it. I swear she was doing her best to show off her nice little tits ever chance she could. The T-shirt she was wearing had some rock band on it and it fit like a second skin.

After the meal my sister said that she and her husband had to go and do some shopping. She suggested that I make myself at home in the family room with the TV while they were gone. I said, "OK." as I watched Caitlin's cute little ass disappear down the hall as she headed for her room.

I settled down to watch some silly sit-com and after about a half hour I was startled to look up and see Caitlin standing in the doorway. She seemed rather subdued compared to how she had acted around her parents. "Uncle Frank, can I ask you some questions?"

"Sure, fire away. Just don't expect me to answer any math questions. I'm not too good in that department."

Caitlin fidgeted a moment, "No, it's nothing like that. It's... ahh... well, we have been doing Sex Ed in school and the teacher told us we should talk to our parents if we had any questions, but I don't want to talk to them. I thought maybe you are you could help me."

I almost fell off the couch, but managed to hide my surprise fairly well, "Sure, I'll try. Just what is it you want to ask?"

"Well, I know all the facts, like how the boy puts his penis in a girls vagina and then the semen comes out of his penis and the sperm swim up into her womb to fertilize her egg and that makes her pregnant." She stopped to catch her breath after blurting that statement out, "But I just don't understand how it works. I was just on the internet looking at one of the sites my friends told me about and now I'm really confused."

"Oh, what kind of site was it? One of those medical encyclopedia types?"

Caitlin blushed, "No, I suppose you would call it a porno site. I know I'm not supposed to look at those but all the kids do. I never did it before tonight. Come on, let me show you and maybe you can tell me why the people are doing... oh, just come see, I can't explain it."

I got up and followed Caitlin down the hall wondering just what I was getting myself into. When we entered her room I looked around for her computer and saw it on a desk in the corner. The screen was black and I could tell by the blinking power light that she had put it on standby. Caitlin sat down at her desk and gave the mouse a shake. In a couple of seconds the screen lit up and I was looking at a full screen picture of a naked girl giving a naked guy a blow job.

Caitlin stared at the picture for a moment, and then turned to me, "Why is he putting his penis in her mouth? He can't make her get pregnant that way, can he?"

I took a deep breath and launched into a rather long explanation about the pleasure aspects of sex and how people sometimes do oral sex just because they don't want the girl to get pregnant. I also tried to explain that girls sometimes did it because they wanted to make the boys penis feel really, really good, without giving up their virginity. I was having a hard time explaining it all without making it sound vulgar. I hoped I was helping her understand without making her even more confused.

I paused, trying to think of what else I should say. Caitlin got a puzzled look on her face, "Does the semen come out of his penis when it is in her mouth?"

"Well, it might." I said hesitantly.

"I'm just so confused", Caitlin sighed, "What makes it come out anyway? Is it like peeing?"

I groaned and launched into another speech, trying to explain what an orgasm was and what made it happen. I told her how there were a lot of ways they could be made to happen and tried to describe some of them. I even told her about how girls have orgasms, too. That seemed to puzzle her, "Why do girls have orgasms? That isn't when the egg comes out, because I learned about the eggs when I starting having my period and they come out automatically."

"It's all part of Natures way of making sure girls get pregnant and keep the human race reproducing. Girls have orgasms because they feel good which makes a girl want to have a boy put his penis in her vagina and make her feel good, thereby making her pregnant. That makes some sense, doesn't it?"

Caitlin sighed, "I guess it does. I don't know why it all has to be so complicated. I still don't really understand what makes the semen come out. I guess I'm just going to have to see it happen to really know."

The room was silent for almost a minute. Caitlin seemed to be deep in thought and I was kind of holding my breath, a little bit terrified by the thoughts that were going through my own head.

Caitlin turned to look at me, her eyes were as big as saucers, "You could show me! Oh, please, I want to see it. Let's make it come out of your penis right now. I won't tell anybody, it will be our secret. Come on, Uncle Frank, you said it felt good. Show me how to do it. Please, let's do it, I want to see it so bad, pleeeeese!"

My mind was reeling. Here was this cute little girl begging to play with my cock and make me come, but, damn, she was too young and there was the incest thing. Jeez, I know I should say no, but my cock was already half hard and trying to convince me to say yes. Then I started to rationalize, I mean, I wasn't going to fuck her or anything like that. Hell, I wouldn't even take her clothes off. It would just be a hand job and she had to learn sometime.

The decision was made for me when Caitlin got out of the chair and moved towards me with a determined look in her eyes. I back peddled until I felt the bed behind me. I was trapped. She dropped to her knees and began working at my belt. In seconds she had my pants opened and she jerked them down to my ankles. Caitlin hooked her fingers in the waist band of my boxers and pulled them down. She froze, her eyes locked on my very hard cock, "Oh, god, it's huge! How could that ever fit in a girl's vagina?"