A little cousin-cousin fun one night when I was 'babysitting' 30 years ago.
This happened to me 30 years ago, when I was 14. My mom went out one night with my aunt (her sister) and left my 9-year-old cousin Linda at our house with me. I was psyched because I was going to get paid $3 an hour to 'baby-sit' and at that age I was looking to make money any way I could.
My mom and aunt were going shopping and then out to dinner and a movie (my dad & uncle were playing golf out of town at some kind of tournament for the weekend) and wouldn't be home until late, and then my aunt and cousin were going to sleep over and the next day we were going to a local lake for the day. My cousin was pretty cool for her age, and we got along ok and were pretty close since they lived pretty close to us and we saw them often.
After I made us dinner (hot dogs and mac & cheese) it was almost 8:00 and I told Linda it was time to take a bath and put her pajamas on. While she was bathing I went to my room and changed into my pajamas (this was 1974 so I was wearing REAL pajamas: long pajama pants, no underwear underneath, and a pajama shirt that buttoned up). I came out and flipped on the TV and found a baseball game to watch, but when Linda came out she didn't want to watch it and said she was bored (we only had 1 TV, no cable in 1974). I told her I had some books in my room she might like and she said ok, so I went and got them and brought them out to the living room. They were mostly about animals (she loved horses and dogs) and she lay on the floor flipping through them while I watched the game.
As she lay there on her belly in front of me I noticed that I could see up under her pajamas (she had on a wool knee length 'nightie' that had frill and lace on it-it was actually a bit small on her) and part of her panties were visible. I couldn't believe it but looking up my little cousin's pajamas actually made me horny. I had been masturbating for about a year, and had progressed to doing it every day (usually at night in bed). I had never seen a naked woman or girl except in a friend's brothers Playboy, but thought about it all the time. I tried not to look but couldn't help myself, and in no time I had a full fledged boner in my pajama pants.
Linda was still looking at the books and had no idea 1) that I could see part of her panties, and 2) that I was hard as a rock. She started giggling at something in the book and then turned over and leaned on her elbow and began to tell me a story about how her mom had taken her to a dog pound a few days ago and 2 of the dogs had been 'doing it'. She was laughing and was very animated, and in my state of arousal I figured I'd ask her some questions. I asked what she meant by 'doing it' and she told me the boy dog was up on his back legs and bumping back and forth against the girl dog (lots of giggles). I said you mean the dog put his thingy in the girl dog and she rolled on the floor laughing (got another great shot of her panties as she did this) and told me yes. I told her that dogs did that all the time and people just didn't usually see them doing that, and that's how puppies were made. She sat up and was still giggling and wanted to know what I meant. I told her that's how dogs and people make babies and she said yeah I know boys and girls 'do it' but wanted to know 'how'.
I thought quickly. I had a book my dad had given me when I was 12 that explained the birds and the bees and had a few good pictures of penises and vaginas and how it all worked. I told Linda I had a book I could show her if she wanted. She said Ok so I practically ran down the hall to my room to get it and brought it back. I sat on the floor next to her, still hard but managing to move in such a way that should wouldn't notice (and it wasn't like she was staring at my crotch). I sat down and explained how boy dogs (and people) put their penis into a girl's vagina and it feels really good and then semen comes out, etc. etc. At first she kept saying 'Ewwwww' and giggling, but then really studied the pictures. She asked a couple of questions, then I did it: I asked her if she wanted to see my penis and how the semen comes out. She laughed hysterically, then when she stopped said how could I make semen come out if I don't put it into a vagina. I told her I can do it with my hand and she giggled some more. All the while I discreetly moved my hands away from my lap (where they had been to hide my erection) and leaned back, making my hard-on very apparent as it tented up my pajamas.
Linda glanced at me and then saw 'the tent' and covered her mouth in surprise. She was still giggling and I told her again I could show her how it works. She didn't say no, and I didn't wait for her to say yes. I simply unsnapped the fly and in a matter of 2 seconds my hard on was out in the air. I told her it was no big deal, every boy and man in the whole world has one and girls and woman see them all the time. I guess that put her at ease and she was sitting cross-legged in front of me, staring at it intently. As I saw she was more comfortable I slipped my pajama bottoms off all together and leaned back against the couch and started to slowly stroke it. I tried to be as casual as possible and explained that it only gets hard like that when a boy is excited and thinking about sex, and that girl's vagina's get wet so that the boy can 'stick it in'. This caused another bout of giggling, and when she stopped (or slowed down) I told her it would be easier for me to make semen come out if she took her pajamas off. She didn't know why she had to do that, and I gave her some cockamamie excuse that she bought. She was very innocent and it didn't seem to be a big deal for her to stand up and take off her pajamas right there in front of me, and when I saw her in her panties I almost came right away. She pulled off her panties (I remember them like it was yesterday; they were white cotton that were pulled up almost to her belly button, and had little pink flowers and blue stars on them) and I saw her smooth slit as she sat back down. I leaned back and began to earnestly jerk off while Linda leaned forward out of complete curiosity and was a mere foot from my cock.
She asked a ton of questions, which helped me from coming too soon, and eventually I asked her if she wanted to touch it. Of course she did, and kind of played with it a bit but never stroked me. I asked her if I could touch her vagina and she said OK, and sat back with her hands planted behind her and opened up her legs. I ran my finger up and down (I had NO idea what to do or where to touch; I just know it felt so soft and warm and she was wet) and she giggled some more and after only about 30 seconds she told me to stop because it felt like she had to pee. I did stop and leaned back against the couch and proceeded to quickly bring myself to the brink of orgasm. I told her I was about to shoot ('what's THAT mean?!' she wanted to know, and I told her) and then it was on me; I let loose with the biggest orgasm I had had in weeks, several long ropes of come that spurted up onto my chest and stomach. And then I was done, feeling terribly guilty but basking in that post-orgasm glow. Linda, not knowing any better, was still chattering away, asking a ton of questions. She got within inches of my belly to inspect my load, but never made a move to touch it. After a minute I got up and told her I had to shower and made a hasty retreat to the bathroom.