My sister in law comes to visit twice a year as my wife and i live in the same town she grew up in. we have a bigger/nicer house than the other sister in town. I work a home office gig and my wife works at a hospital, so we have alot of alone time. We've always been kinda flirty, and I always have thought about her sexually. I know from my wife, that she's in a sexless marriage and has been having an affair with a coworker for over a year. She is about 10 years older than me and her lover is like 5 years younger.

During her last visit I was working in my office, which is right next to where she sleeps and near the bathroom with the shower. She came in, in her robe and was just being silly with me, chatting about nothing and so on. So i tell her that she needs to let me work or else, to which she replies "what are you gonna do?"

I stood up and grabbed her, pulled her down on top of my lap as i sat down on the couch and held her tightly. I whispered in her ear "im going to tickle you". she gasped and shrieked "i'm naked under my robe". i just laughed and held her tight. "naked huh? well maybe i should just let you go take a shower then". I let her go, but held on to the strap of her robe and let it fling open as she got up.

Not that i could actually see the front of her robe when she whirled, as her back was too me, but it was really exciting and i was very turned on at this point. she turned around quickly and gave me a big smile. I jumped up from the couch and started kissing her immediately. she kissed me back and i started caressing her naked body under her open robe. for a woman nearing 40, her body was quite nice. flat tummy, shapely ass and firm c-cup tits. it wasnt long after that i had my hands, then mouth on her tits. i slid my hands down her body and started feeling her pussy it was hairy and wet. i rubbed her clit with my index finger while i sucked on a nipple.

my head was racing. i knew i had to fuck her, but where? i couldnt bring her to my bedroom to fuck, and i was afraid we would leave too much evidence in the office. I carried her back to the guest room, where she was staying and laid her down on the bed. it was then that i went down on her, tonguing her pussy till she came several times. she later told me she hadnt had her pussy licked in quite sometime, as her husband doesnt do that. (she never told me about her lover, but i assume he doesnt either, the way she carried on).

at this point in time i was dripping with precum. i didnt ask, i just pulled off my jeans and let my cock pop out. i straddled her up high so that i could lay my cock in between her tits. she reached up and stroked my six inch cock, cooing. my wife would normally push my cock right in her mouth as she loves it, but sister in law wasnt offering her services. i slid my body on top of her and whispered in her ear "im going to fuck you now". i pushed my cock into her pussy and it was warm and wet. she wrapped her legs tight around my waist and arched her back while i rolled my hips nice and slow and deep. she squeezed me hard and came again. i pushed her legs onto my shoulder and burrowed in deeper, jackhammering her hard as she screamed. she begged me to cum, but i was way too numb and overstimulated at this point. I suggested she get on all fours and let me fuck her from behind. her ass looked fantastic as she bent over and spread her pussy lips open for me. i slid right back in and was hitting her hard. her juices were all over me, practically down to my knees as she came again.

she insisted that i needed to cum so i had her get down on her knees and suck me. it was obvious that this wasnt something she did, as she was terrible at it. i had better bjs in high school. i asked her where she wanted me to cum and she replied "anywhere but my face", i practically laughed at this. I suggested we get in the shower. i had her kneel down on the floor and hold her tits together while i jerked it. She was talking dirty to me, begging for me to cum on her tits. I felt it coming on and started pumping my cock harder and harder. all i could think about was how hot it would be to cover her face with my cum. i pointed my cock up higher and spurted a huge load all over her face as she shrieked. i just laughed and turned the shower on. she quickly forgave me after i washed her hair and body from head to toe.

the next day when we were alone she told me that my wife had mentioned what a great mood she seemed to be in, and then confessed that she was sore from fucking, but a good sore.

fast forward 10 years later and she's not as hot and kinda a drunk. i have kids and i'm all responsible, so no more sister in law fucking for me....