(This is a true story that happened a couple of years ago. I was 29 years old at that time and was married. Luckily for me, I still am!!) I was going through a career change, so my wife started working to help us through. She is a very pretty girl, very sweet natured. We had been married for 5 years then and had an angel of a daughter. My wife is very conservative and not a whole lot interested in sex, which why what's in this story actually happened. Because my wife was working and so was I, my father-in-law suggested to let my sister-in-law stay with us to take care of our daughter. Moreover, she was not getting along with my step-mother-in-law at all and they would fight almost every day and my house is very close by. My sister-in-law is 5'4", 115 lbs, has small breasts and the cutest ass you could imagine. She was just a month away from her 18th birthday. My wife's family is very conservative, so my sister-in-law was not allowed to go out by herself or have any male friends. Actually the only guy she could go anywhere with, other than her father and her brother (who is also married and about the same age as me), was me and her relationship with me was more of an elder brother. She liked me and loved to play around with my daughter so she was excited at the thought that she can live with us. She had spent few nights here and there with us and as everybody in my wife's family knows me as a decent guy, nobody had any problems with her living with us. Well, the first month was usual and when I come home from work and my wife left for hers my sister-in-law (lets call her Nikki) would talk to me about casual stuff and will also cook some dinner for me and we will watch TV together even after I put my daughter in her crib until either my wife comes back from work or I decide I can't stay up any longer. Nikki's 18th birthday also came and went and it was not anything special. One day when I went in the shower after I came home from work, I heard Nikki whispering in the back yard. I looked through the blinds and saw Nikki in the backyard sitting on the swing with a phone in her hand. I got curious so walked into the bedroom and picked up the other phone turned it on. I heard a male voice on the other side and the guy was trying to sound very sexy and passionate and was asking her how she could go out alone without any of her family members so he can take her to a motel or something. Nikki seemed like she was enjoying the conversation but was putting off his offer to take her somewhere. It did not took me long to understand what was going on and I felt it was my duty to do something as my wife's family had given her responsibility to me. I put on some clothes and walked out into the backyard with the phone still in my hand and now I turned on the speaker-phone. As soon as Nikki saw me, she was obviously shocked and terrified at the same time. She just said "brother" and hung-up and before I turned off the phone I heard the guy say "shit" before he hung up too. I started to ask Nikki what was going on. My calm voice appeared make her a little relaxed but she was still afraid and was apologizing and begging me not to tell my father-in-law, my brother-in-law or my wife. At this point I felt sorry for her and held her hand and took her inside and sat her on the couch. I told her that I will not tell anybody as long as she tell me exactly what is going on, who is the guy and how far have they gone. She told me she met him at the new job that she started just a couple of days ago and the guy just handed her a piece of paper with his telephone no on it, and today was the second time she called her, so she was curious. During all this counseling and her sobbing and explaining how all her friends made fun of her for not able to go out with them, let alone have a boyfriend, was making her curious, I did not even realize that I never let go of her hand and that she was sitting right next to me on the couch and now was putting her head against my shoulder, (which by the way was bare) as I only put on a loose tank top and a pair of shorts before I stepped out in the backyard. Nikki kept rubbing her face and head against my shoulder and kept on complaining about how she has no one to hear her problems or answer her questions about her own body. Now, that was making me feel so sorry for her that I was consoling her and listening her out. Nikki very innocently and unknowingly was going from her complaining to telling me how her friends told her in detail their first sexual experience and sometimes more vividly to make her jealous or to tease her. Her narration of her friends' sex stories was giving me a hard on, and I was not even paying attention towards it when all of a sudden my cock twitched in my loose shorts and I guess both Nikki and me caught the action at the same time. I was so embarrassed that I quickly let go of Nikki's hand and try to cover my cock with my hands, which was making a tent in my shorts. Let me stop here and tell you that I have an average size cock at 7.5" long and about 3.5" in diameter. Both Nikki & me were quiet in an awkward silence when all of a sudden Nikki got up and knelt in from of me and joined her hands and begged me to show her my cock. I was shocked and wanted to yell at Nikki for being so shameless, but her begging and tearful eyes stopped me. She then told me that if I agree to her request, she would not call that guy ever and not talk to him at all. She also told me that she knew her father was already talking to his friend about marrying her to his son and that she was fine with it but she does not feel comfortable in getting married without knowing anything about sexuality. Let me tell you here that most of the marriages in our culture are arranged and even though I saw my wife and fell for her beauty, the only way to get married to her was to have my parents talk to her parents. I remembered that my wife was so scared about having sex after we got married that it took me over a week to make her comfortable before we could have sex (she was a virgin too) and believe me, it was not fun at all for first couple times. Listening to Nikki beg was having its effect on me and just the thought the girl I secretly used to mentally undress is on her knees trying to undress me was turning me on to the point that my cock started to control my brains. I told Nikki that the only way she could see it is that first she has to uncover it herself, second she cannot tell anybody about that and that this would be the first and last time she could do it. Nikki said yes in a hurry and I could see the sparkle in her eyes. I thought to myself, well worst comes to worst she will blow me (which I needed bad as her sister will not do it at all) and that all I am doing is to help her understand her sexuality so she is not like her sister when she gets married (boy, was I wrong!) So Nikki scooted forward on her knees and came closer to me, I took off my hands off my lap and my cock sprung back to make a tent in my shorts. She put her trembling hands on my cock and it started growing even bigger. She stroked it through the fabric of my shorts and then suddenly she pushed on the leg of my shorts up to expose my cock. She then held it in her hands and the contact of her warm hands on my cock made me wild and I put my hand over her and showed her how to stroke it up and down. Nikki seemed to be an intelligent student and picked right up. Then without warning she lowered her face and first kissed the tip of my cock and then right after she put it in her mouth about half way in. "Oh my God!" I shouted and all of a sudden I was in heaven. I held her head and bobbed it up and down on my cock, as she did not know how to give a blowjob. Then while I was enjoying what was going on, she stopped abruptly and stood up. I had no idea what to think when she said she want to hold me naked to herself and took her shirt off. I noticed she had no bra on and her small and perfectly rounded breasts stood proudly with pink nipples on them. I was so admiring her breasts that I did not even think about stopping her. Actually I couldn't have done it even if I wanted to, as logical part of my brains were now completely shut down and I think I even helped her remove my shirt and then she sat on my lap and put both arms around my neck and started to kiss me. Her full lips were so good that I kissed her back and in the process showed her how to kiss as she was very inexperienced and I could tell she was trying to copy some late night shows. But did I mention she was a very fast learner and picked up right on the cue. I was unknowingly searching for her breasts and started squeezing them slowly while Nikki reached down to my now unattended cock and started stroking it slowly while never stopping to kiss me. At this point the animal in me was released and I laid her on the couch with taking my shorts off in one move, not thinking what I was doing. Then I hooked my fingers on the belt of her sports pant when she surprised me by hooking her fingers in the elastic on her panties and following my downward motion while lifted her hips up to help take both of them off at the same time. There she was lying there naked in front of me fully exposed to probably the first guy ever in her life. Her pubic mound was thick in growth, but her pussy lips were so thick that you could see them even through the hair. I lowered my face into the bush and found her clit and started licking and biting it. This made Nikki wild and started pushing her pelvis at me while breathing heavily and uttering words that only she could have understood. When I looked up, I could see her biting her lips and clawing her nails into the fabric of the couch. Then I just sat up and knelt in front of her between her legs and started rubbing the tip of my cock on her pussy lips and Nikki was now getting louder and louder. Suddenly she said " Sunny, please put it in, please put it all in, fuck me please." She held my cock and pointed it to the opening of her pussy and tried to pull it in. In the back of my mind I was thinking I should not do this, but my cock was trying to push at opening of her pussy as if in a mind of its own helped by Nikki. Finally I got the control enough to stop and asked her, "Nikki, are you sure you want to do this? It might hurt at first and you might bleed a little too." At this she reaches out to her clothes that were lying on the floor next to the couch and tucks them beneath her ass and then sits up and holds my face in both of her hands and says, "Sunny, I know you will be gentle with me, that is why I want to do it with you. Moreover I can trust you for not making me pregnant, as you are experienced and care about my future. Please do it to me, otherwise I have no choice other than to go out and take more risk with someone I don't know as well," and she plants a soft kiss on my lips, (...aaah, that feeling!) and she lays back on the couch in the earlier position and looks at me in a mixture of greed, lust and love that I couldn't explain. I thought to myself "What the hell. She is determined to get it soon anyway, why can't it be with me?" and she is right; what if the punk she sleeps with first, doesn't care and drops his seed into her? She don't know any better and there is nobody that can advise her. I said, "All right Nikki, you asked for it. Now just relax your muscles and promise to let me know when it starts to hurt and I will stop." She looks at me, smiles, and then closes her eyes. I put a lot of saliva on my fingers and rub it on the tip of my cock. I could see the moisture glistening on her pussy lips and was amazed at how wet she is. As I put the tip of cock at the opening of her pussy she lets out an "aaah" and opens her eyes briefly to look in my eyes before closing them again. I hold my cock and start to push a little. I could feel the folds of her pussy opening and half of the tip of my cock disappearing in her. She was so tight that I remembered her being tighter than my wife during our first time. I stopped, and then pushed a little further, as I see almost all of the tip going in. Now I could feel her stomach muscles stiffen where my left hand was and she squealed, "Stop, stop for a bit but don't take it out." Then she opens her eyes and I could see the pain and a hint of tears in her eyes. I said, "Nikki we can stop right here if it hurts a lot, but if you want to go further, just remember to relax your muscles around your waist, as that will help a lot." I could feel her relax and I bent over to kiss her. Now let me tell you that the thickest part of my cock is the tip. So I knew if the tip went in it will be downhill from there. Then I pushed a little further and felt the hymen give in. I see Nikki's face and her eyes are closed tight and I can see the pain in her eyes. Once the hymen broke, my cock kept on inching further and I can see Nikki opening her eyes and felt her muscles relax. Once I had the whole shaft in, I lay on top of her and started to kiss her with my cock fully buried in her warm and incredibly tight pussy. After lying there for a while, I felt Nikki thrust her pelvis towards me in rhythm. I got the clue and I started to pull out my cock until just the tip was in and then went slowly back in, all the way in. Nikki breathes heavy and holds me tightly against her and I could feel that she is raising her legs and widening them at the same time to give me better access and meanwhile she is kissing me madly. I kept my long and smooth strokes with some stopping at the either end to make her adjust to me and saw that it was driving her wild and she keeps saying my name whenever she breaks her kiss, "Ooooh Sunny! Mmmmm, oooh Sun....mmmmmm.." Slowly I raised the speed, but you could still consider it way slow than even a normal slow fuck. I guess this was making her wild and she realized the faster it is, the more stimulation she gets. Now she raises her hips and meets with her own stroke and she keeps gaining momentum making me match her moves and in turn making her wilder. Then she breaks the kiss and starts shouting, "OMG, Sunny, please faster, please fuck me faster. Mmmmm .... oooh.... God, fuck me fast Sunny, take me, put it all in, mmmmm … Mmmmm... OMG, faster, harder, faster!" and all combinations of these words. At one point she was saying these words in no combination at all, but it all sounded too good. I sat on my knees and held her legs over my shoulders and this gave her room to throw her hips wildly at me and she started yelling. I was afraid my in-laws would hear it across few houses. I was pounding her mercilessly (which her sister can't take even after a baby) and this little slut was obviously enjoying it to the limit. At one point I thought about pulling out and turning her on her stomach (doggy style is my favourite position), but every time I would try to do that she would latch onto my butt and wouldn't let me do it. I was amazed at her strength and was scared she will not let me pull out in time when I cum, so I bent on her slowing for a second and told her that she need to let me go when I ask so I do not cum in her. I guess she understood what it meant, and nodded her head breathlessly. Now relaxed of that fear, I started to give it to her really good and she responded with sometimes getting louder and sometimes getting really quiet and just breathing really fast and heavy. At one point she surprised me with hissing so loud that I thought all the snakes in California would come sliding in my house. After a while she started tensing her muscles to a point that I thought the skin would come off my cock before letting go. That did it for me, and I pulled out just in time before the first wave of my cum came gushing out and the first squirt landed on her neck just under her chin and the rest followed on her chest, stomach and her pubic mound. I had my fair share of pussies, but I swear I never felt so good or ever remember cumming so hard. I fell on top of her and we both kept breathing hard and heavy until we got the energy to get up. As soon as I got off of her, she grabbed her clothes and hurried off to the bathroom without saying a word. I got off too and walked into the master bathroom and got under the shower and washed off the little blood off of my now shrinking cock, which for the first time felt a little sore after a fuck session. While I was taking shower I couldn't help but wonder if she is repenting at her decision now, and why she did not say a word before taking off to the bathroom, and then mixed thoughts of a lifetime of a pleasure that I just got; a little guilt and thoughts about whether that was real. I thought this will be the first and last time I got something like that (was I dead wrong?...again?) When I came out of the shower I went into the living room and sat on the couch. Nikki came out of the bathroom in new clothes and sat right beside me holding my upper arm close to her chest with her face down. I lifted her face and kissed her on her lips and then she softly said, "Thank you." (if you liked this I have a few exciting encounters that I might send in, so please vote)