A few months ago my sisters boyfriend whom she lives with came over with his laptop and asked me if i could have a look at it for him.He said it was unusable and figured it was busted. My sister who is 22 was not with him at the time and he left it with me for the weekend.Although i was just 16 i had more PC knowledge then both off them put together. That Saturday night i was alone in my room so i decided to try and fix it for him. Within minutes i figured it out, the guy had that MBlaster virus and it just kept sutting down on him. I upgraded him to Sp2 and put AVG on it. During the virus scan other viruses were found but more notably was the folders they were in "...Holiday2004SonyMVC", i knew they were in france that year so i open the folder i started flicking through the pictures. Within seconds i noticed a few snaps of my sister semi-naked. I was surprised at how horny and excited i felt looking at her and the pictures were'nt even that revealing. I made a copy of the pictures and cleared the documents history to cover my tracks. I gave him back his laptop on Sunday and he was delighted and even gave me £20 for my trouble. Sunday night i couldnt get to sleep thinking about the pictures but i kept telling myself that it was sick to think of your sister that way but i couldnt get asleep. At about 3Oc in the morning i got up booted my pc and decided i had to do this one thing, just to get it out of my system. I set the pictures as my screen-saver slideshow and sat back cock in hand. As the pictures flicked across the screen my strokes got harder and faster, my eyes taking in every bit of my sister body and loving the fact it was so perverted and dirty until finally i released all over my knuckles and leg. Imediately i felt dirty and sick at what id done and quickly deleted the images from my pc and turned it off and went to be feeling immense guilt. The next few weeks went by and i tried to not think anymore sexual thoughts about my sister, then one week she decided to come home for the weekend on her own. I did masturbate while lying in her bed in her room the night before she arrived but other than that i wasnt planning any "fuck my sister" scheme which i dont believe anybody has ever done successfully. My sister arrived that Saturday morning and put her suitcase in her room. She came down to the kitchen for a chat and a coffee, and as she sat there all i could do was to stare at her chest and think 'i tossed off looking at your tits!'. She got up and went to have a shower before dinner and i figured this would be my opportunity to glance at her naked and in the flesh. But for all my trying she never came out undressed or in a towel that my accidentally fall off, or mistakenly leave the door ajar while she undressed. I was really horny now, full to the brim and bursting with spunk, 'god i wish she'd just ask me to look at her new bra or some benign lump on her tit!' i thought. Around 7Oc she left to got out with her friends to some club and i sat down to watch some tv plotting that she might get undressed for bed drunk and leave the door ajar. All these stupid ideas flood through your mind when you really want something your never goona have and only make you even more horny and frustrated. I downed a few beers around 11Oc and was 'half shot' when she came back at 2:30 am, she was telling me about her night which seemed quite good and having a few vodkas in the sitting room. Then after one vodka too many mom got out of bed and basically carried her to her room. I was fairly sober and when mom came down and explained that my sister was 'out of it' i felt like going to bed myself except she also told me she was so drunk that she had to undress her for bed. Now my mind went rampent, she was up there naked under the covers and out cold! I went straight to my room saying i was tired. I waited untill everybody had gone back to bed and was well asleep. This would probably be my only chance to she her totally nude and not in a picture. I had to savour this moment, so i got my dads video camera from downstairs. Fuck it! i thought ill video her nude and that way i could always watch it when i got the horn for her. I loaded the camera and turned it on in my room so that enoying beeps it makes wouldnt wake her up. Its funny how everything is much louder when your trying to be quiet. I snook down the hall and slowly opened her room door. 'Fuck it!' her light was turned off and i wasnt going to turn it on. I fiddled with the camera in the dark until i found the 'night vision' switch. 'BEEP!BEEP!' fuck that camera anything you do with it makes a noise. The viewfinder lit up in a green image and i used that to see around the room. There she was out cold looking almost dead in the green viewfinder. She was covered up by a douvet but i decided to risk pulling it back slowly. I managed to pull it back all the way to her waist revealing her breast's. Jesus i was horny i was shaking, my heart thumping in my chest and every breath sounded louder then the last. She didnt even twitch when i pulled back the covers so after videoing her tits as much as i could i decided that i would get away with a quick wank. I dropped my pants letting my cock stand proud infront of her in the darkness of her room. I could feel its head throbb almost as if it would cum there and then. If only she knew her brother was there looking at her chest and sporting the hardest errection he had ever had. I did the difficult task of holding the camera and stroking with my left hand. My pre-cum spilled over my head and shaft making the expierence very pleasurable. There i was stroking away for my half naked sister getting ready to release a hot load for her in her room. I dont know if it was the beer or a ' might aswell be done for a sheep then a lamb' attitude but i thought id risk cumming on her, 'yeah fuck it!....just do it, all over her tits.....no her face!..shell wont wake up', god i hoped i was right, i wont be able to explain this away if she caught me and id be known as a perverted incest freak by my parents and worse her boyfriend and whoever he wanted to tell over a beer. I leaned foward slowly placing one knee on her pillow beside her head (very risky) the bed made the loudest creek ever made by any bed anywhere. Nothing, not even a blink of an eyelid! God i was going to get away with this, and video it as a bonus! I lowered my cock over her lips and tried to steady the camera. I only got about five slow strokes before i started to cum causing me to judder forward. Pump after pump it spewed onto her lips and cheek, fuck it felt so good.I was trying my hardest not to jerk the bed while i was cumming. Watching my hot cock spurt my sperm onto her mouth was so nice. Within seconds i was finished, i only lingered long enough to try and video her face now wet with my spunk but i was now so nervous i couldnt work the focus properly. I quickly left and went back to my room, at first i was so frieghtned that she wake up tomorrow and realise that her brother had jerked off on her face! but soon that was replaced with feelings of 'i should do it again, i wont get another chance' and my now limp cock began to grow again. This time i was quicker and braver, knowing that she wasnt going to wake up. When i entered her room she was still half naked but had moved onto her left side. I couldnt see any evidence of my last visit on her face but i soon got to work giving her another facial. This time my spunk was less her position made it hard to get close to her face but i did shoot onto her hair, cheek and ear before running back to my room, this time for good. The rest of that night and early morning i was really terrified that id gone too far and my dirty secret would be out. I even planned to say i had a friend over at 5 in the morning and he must of done it, how fuckn lame was that. But any of you who also would like to cum on your sister(basically anybody reading this) would know what i mean. And here is the best bit of this story, she woke up came downstairs and said to me that she knew what i did and wanted to suck me off!.....only joking she came down and said that she was so drunk she thought she had gotten sick last night and her hair was stuck to her face this morning. What i learnt from that is that if a person doesnt know, there is know way theyll suspect that you wanked on there head it just doesnt enter there mind, but be warned if they have any, and i mean ANY idea that you might find them even remotely attractive it will enter their mind and then your fucked. This story is true.....i still have the tape.