My wife was away one weekend for a shopping trip to London with her mum. It was one of my mates birthday, and all the lads were going into town for a night out. So that I could go I had arranged for my brother and his girlfriend to come over and look after the kids and as I knew I would be out late they were staying over so as to not have to worry about waiting up late for me. Anyway, the night out was a bit disappointing, and so I decided to head home fairly early. I got home about mid-night and let myself into the house, making as little noise as possible assuming that everyone would be in bed. As I turned from closing the front door, I could hear moaning sounds coming from the lounge. I giggled a bit, thinking my brother was shagging his girlfriend, and whilst contemplating barging in on them for a laugh, I thought better of it as baby-sitters are priceless! I tip-toed up the stairs, and as I walked past the spare room, I could hear really load snoring. I poked my head in and my brother was flat-out on the bed (alone), therefore posing the obvious question as to what was going on downstairs. I crept back down stairs and listened at the door, and heard the unmistakable sounds of a woman’s orgasmic moaning. I opened the door, and my brother’s girlfriend was sat in the arm-chair with her legs spread over the arms rubbing her clit frantically. The fantasy channel was on the tv. She looked at me with horror and started muttering, whilst going scarlet red. My eyes were fixed to her shaved cunt, which shone in the light of the tv with her juices. I cannot recall what she was saying as I couldn’t help but look and couldn’t help but get a hard on. She stood up to go, but I told her that she should finish what she started, and that I might even join her. She moved towards me and kissed me hard, pushing her tongue into my mouth. I knew I shouldn’t but you don’t look a gift horse… I removed her top, and the biggest pair of tits I have ever seen came into view. She is a fairly large girl (size 16 – 18) and her tits were heavenly. I sucked on one whilst playing with the other nipple and she began moaning again. Her nipples were obviously very sensitive. She had undone my trousers and pulled them down past my knees and was wanking me very hard and rough. I had to stop her as it was quite painful. I pushed her back into the chair and lifted her legs back over the arms and moved downwards so I could lick her cunt. She went absolutely crazy, shouting and screaming with pleasure. I stopped as I was sure my brother would hear, but she told me to carry on and that he had drunk 3 bottles of wine so would be well out. I carried on licking her clit and pushed three fingers in her easily and she orgasmed immediately. I have heard that some women spurt when they came but had never experienced it until now. I was soaking. When she recovered, she pushed me down onto the floor and began sucking my cock. Again, she was very rough and a bit of a tooth scraper so I had to stop her. She told me that her and my brother hardly had sex and that when they did it was always straight down to it missionary style. I moved up her body and put my cock between her huge tits and began to tit-fuck her. This was absolute heaven and I was so turned on that I knew I wasn’t going to last long. I soon spurted my come all over her tits and she was fascinated watching it. We kissed passionately again, and chatted for a while. She revealed she had only ever slept with my brother and that he never did anything. On the tv, a woman was imitating a blow job with a dildo, so I jokingly said “that is how you do it properly”. With that, she started sucking me again, bringing my cock back to life. She was copying the woman on the screen and this time it was great. Her tongue technique was even better than my wifes which is saying something. I soon knew I wasn’t far off coming again, and felt it only fair to warn her expecting her to stop. But she quickened her pace and I spurted into her mouth. She swallowed the lot, and told me she loved it. She kissed me again passionately though I had to pull away as I didn’t share her love of the taste. I went back to licking her pussy, and again she came with a spurt. I was hard again at this point and was desperate to fuck her. I ran my cock against her clit for a while to tease her. She was pleading for me to fuck her, and so I pushed my cock in right upto the hilt with one push. This made her come again straight away. I began thrusting slowly at first, and she was howling. I was kissing her to try to stifle her noise. As I had already come twice I knew that I would last a while. I turned her over and fucked her doggy style, and again her noises were incredible. I had my hands on her swaying tits as I fucked her. Then I decided I wanted to fuck her arse. As I was fucking her, I started fingering her arse, scooping up the juices from around her legs to lube it up. She startled at first and pulled forward, but I carried on fucking her and probing her arse with my fingers. She soon was right into it, and as I felt she had loosened up enough pulled my cock out of her cunt and pushed it against her arse. Slowly I pushed it in and she screamed that it hurt. I reassured her that it would settle down if she relaxed. Bit by bit I pushed my cock into her arse until it was all the way in. I stayed still for a bit and asked her if it was ok. She said just fuck my arse will you, so I slowly started fucking her again. As I was fucking her arse, I moved my hand around to rub her clit, which sent her over the edge again. I couldn’t last any longer and shot my load up her arse. We lay on the floor, gasping for breath, and it was then that the reality kicked in. I had just fucked my brothers girlfriend. I was silent and feeling guilty and she asked me what I was thinking. I told her and she said she would not tell anybody. In fact she said she would love to repeat it, and so I regularly meet up with her to fuck her. She loves anal now, which is great because my wife won’t contemplate the idea. I have even suggested we go to a swinging club and she has agreed, which again is great as my wife wont.