True experience that happened when I was 10. That was when I learned how all guys love to jerk off and think with their dicks!
My first 'sexual experience' occurred when I was about 10. My brother is four years older than me, and he used to hang out with this kid Ned. One day my brother and Ned were upstairs hanging out in his room and I was downstairs watching TV. I'm not sure where my mom was, but I know she wasn't home, and my dad was at work. It was the summertime.
All of a sudden I heard the door to my brother's room bang open and lots of commotion, laughing and giggling. I could tell they were up to something, they always were, and it was usually pretty stupid, so I ignored it. Their noise stopped as quick as it started, and I figured they went back into their room. A minute later out of the corner of my eye I see Ned coming down the last few steps on the stairs (the upper steps were hidden by a wall) wearing nothing but his underpants. He walked across the living room in front of me, not saying a word, and then he burst out laughing and ran into the kitchen. I thought he was a jerk for doing that, and not 10 seconds later my brother came running through the TV room in just HIS underwear. I went into the kitchen and they were both busting up laughing, and I asked them what they were doing. They said they were just doing dares and I should lighten up, and they would kill me if I told my mom.
I couldn't help to look at their underpants, and I noticed that they both had boners. Even at 10 I knew what that was. I had a pretty sophisticated best friend who had told me about boys, erections, sex, etc. the previous summer. I was curious like any girl that age, but not obsessed with it like my 14 yr old brother and his friend.
I told them I wouldn't tell, and also told them that I thought they were dumb and went back into the TV room. In the back of my mind I had actually liked seeing them in their underwear because like any kid I was curious about what a boy (or other girl) looked like naked, and underwear was the next best thing. I went back to watching my show, and just a few minutes later Ned and my brother came bursting through the door, walking quickly (not running) and laughing - COMPLETELY NAKED! Ned twirled around right in front of me, like he purposely wanted me to see all of his body, and in a flash they were gone up the stairs.
I sat their for a few seconds, dumbfounded, trying to let what I had just seen sink in. I was scared, embarrassed, and more curious than ever. I had noticed Ned's thick thatch of black pubic hair above his penis, and how his penis stuck straight out from his body. My brother only had a little bit of pubic hair, and his penis seemed to be smaller than Ned's but it was also sticking out, but more pointing up towards his belly. The more I thought about it the more I wanted to see them naked again (especially Ned).
I ran upstairs and the first thing I noticed was that they hadn't shut the bedroom door. The next thing I saw was that they were sitting next to each other on the bed with their backs to me, still naked. I just walked in and they just ignored me, and when I walked in front of them they pretended to be surprised and Ned took a book or magazine he had been reading and tried to hide it behind his back. Neither one of them tried to hide their privates, and I couldn't help but stare at them. After a few seconds I asked Ned what was behind his back and he smiled, and without me having to ask again brought it around and handed it to me and said it was a girly book he stole from his brothers room. I opened it and saw pictures of naked women mostly, and a few men, and I distinctly remember that was the moment I felt the tingling between my legs.
As I looked at the pictures Ned and my brother were whispering to each other and laughing, until my brother finally said that since I got to see them naked they wanted to see me naked. I said no way, but I wanted to stay in the room with them because I was getting to look at NAKED BOYS (especially Ned) and a dirty magazine. They kept asking, and then they were pleading and Ned said if I did get naked he would show me how he could make sperm. I knew what he was talking about, and with everything I had been exposed to in just the prior 15 minutes or so I was VERY curious about seeing him 'make sperm'. I had heard about boys jerking off, but didn't really know how they did it, or why.
So finally I said I would make a deal; I would take off my shorts and tshirt and then he would have to make sperm, and he said ok. I was REALLY embarrassed (not so much because my brother was there, because he saw me in my underwear tons of times, same for me, but we hadn't seen each other naked since we were really little). I took off my tshirt (I had on a training bra) and then I pulled down my shorts. Ned was saying things like 'Wow' and 'Awesome' and he started pulling on his penis. As he did he was groaning and stuff and my brother was really just sitting there watching. I stood there like a dope in my underwear while they sat on the bed next to each other, naked, with Ned pulling on his erection. Then he stopped and said he REALLY wanted to see me naked, as he had never seen a girl naked and kept saying please, please, please so finally I said alright.
I did it real quick or else I would have chickened out. I took off my bra (I really had just started to develop) and then quickly yanked off my underpants and kicked them aside. I instinctively put my hands in front of myself to cover my privates, but Ned and my brother said no, move your hands, put them on your hips. So I did, and Ned was really pulling on his penis then and I noticed my brother was too. Ned told me to turn around for a second, and I thought they didn't want me to see them do something but when I did Ned said Wow you have a nice butt and I heard my brother say yeah and then I felt a hand feeling my butt cheeks. It actually felt nice but I was scared so after a few seconds I stepped away and Ned stopped. I turned around and they were both rubbing and pulling really, really fast and Ned stood up and was standing about a foot away from me and he asked if he could touch my 'tit'. I told him ok but just a little and he started feeling and kneading my little boobs while his other hand was pumping like crazy. Then he groaned really loud and said ah here comes my sperm and he took a step back and it all started to come out of his penis. A little actually shot up in the air a bit (it reminded me of a movie of a volcano I had seen just a few weeks before on some nature channel) and then a whole bunch kinda just plopped out and went on his hand and the floor. I heard my brother groan (a lot quieter than Ned) and saw his sperm come out too, but a lot less and it just sort of dribbled all over his hand and into his pubic hair.
So that was it. They didn't say anything to me and I just got dressed and left. I didn't even see if they wiped all the sperm up. I didn't care, it was his room. After Ned left later though my brother told me to swear I wouldn't tell what happened, and I did. Even though I got a little horny from seeing them jerk off, I didn't go and masturbate or anything (I didn't know how!). Actually I didn't start doing that for a couple more years, and once when I was 13 and my brother had just turned 17 we actually did it in front of each other (but that was pretty weird). I masturbate about three to four times a week now and absolutely love it (I'm a 'clit' girl and can come from stimulation here in a matter of seconds...), and have discovered I'm a bit of an exhibitionist. I have a story I'll share another time about undressing and masturbating one time in the summer with my windows and blinds wide open. I was 15 and my mom, brother and I lived in an apartment right after she and my dad got divorced. I still hadn't filled out much at that point (I didn't really 'blossom' until I was 16) but this older heavy guy who was about 40 watched me from his window across the courtyard and I could see him jerking off while he watched. I liked that A LOT because it made me feel very sexy.
Hope you like the story of my experience and I hope I wrote it down OK. Happy jacking and jilling everyone!