Slut Wife - Sister

"Don't even think about it Loser!" laughed my sis-in-law as I was about to walk into the bathroom for my morning shower. I stopped and turned to look back as she quickly pushed past me wearing just her nightie which hardly covered her ass. Ellen's sister, Karen, was hot. I know its probably wrong for a man to think like that about his sister-in-law but I'm only human!! Ellen's parents had Karen later in life, so she was only half her age. She always used to joke that her sister was a mistake. Some mistake!! At 18yo, Karen had just started Uni and was staying with us to save money till she could afford a place of her own. I didn't mind because she was a fox!! Karen had been just a small child when Ellen and I first got together, but now she was grown up, we were the best of friends. She often teased me by saying I was pretty cool "for an old guy!!" It was mid-Saturday morning and I had slept in a bit after working late the night before. Ellen had gone out shopping. Wearing only a singlet and a pair of boxer shorts, my semi-hard morning wood was on show. I had been stumbling towards the bathroom thinking of a hot shower and a good wank to start the day, So much for those plans... As my sis-in-law passed by me I noticed her eyes scanning my body and hover where my cock pressed against my underwear. "I'm showering first so you can wait your turn", she said as she pushed through the door and into the bathroom. "Besides by the look of it, you'll need to take care of things in here and I don't want to be waiting around for ever!!" she laughed giving my semi-hard cock another look. It wasn't the first time she had made such comments and because of our close relationship I just laughed it off. Still half asleep I followed her into the bathroom anyway and went to the basin and gave my face a splash with some cold water. Despite what she'd said about waiting my turn, Karen obviously didn't object to me being there as she reached behind me to shut the door and then started the taps on the shower. As I stood leaning against the bathroom sink looking at my slightly blood shot eyes in the mirror, I suddenly realised that my sis-in-law was pulling her nightie over her head!! My eyes were glued to the image of her nubile young body in the mirror as her pussy came into view followed by her pert little breasts. Her pussy was covered in soft blonde hair and looked like it hadn't been shaven in a while and her tits, well... wow!! They were awesome, standing firm and pointy without a hint of sag!! My eyes were feasting on her body until I realised she was staring right at me!! My arms went a little weak and I snapped back to reality as she said, "Had a good perv?" I span around to apologise but to my utter surprise she just said, "Don't be sorry. I find it flattering that you would look at my body that way and by the looks of things, you liked what you saw" she grinned. Her eyes again went to my crotch and as I looked down I realised I had come to full attention and was nearly poking out the top of my boxers!! With that, she turned away and gave me a glimpse of her tight little arse before stepping into the shower. I stood and watched for a few seconds then turned around and grabbed my tooth brush to try and keep myself busy. I stood brushing my teeth but my eyes kept looking back to the image of Karen in the mirror. She was washing her hair with her eyes closed but was facing me, giving me a prime view of her sweet young body. I was still staring at her when she opened her eyes and caught me perving at her again. She didn't say anything this time, instead lathering up some soap in her hands and washing her body as she maintained eye contact with me. Her hands ran over her breasts and down over her tummy which was so flat and toned. My eyes were glued to her. She didn't try and turn around or cover herself up, just kept running her hands over her body. Her hands went down to her pussy and she rubbed it a little making my mouth drop open in awe. Suddenly she turned around and I thought maybe she had taken things as far as she wanted, so I went back back to brushing my teeth. Then I heard her say "Could you bring over your razor, I need to use it". I spat out what tooth paste I had left in my mouth and slowly reached into the side draw to grab my razor. In the past I'd complained about her and Ellen using my razor but I must admit I'd never thought she was shaving her pussy with it. I always assumed it had been her legs or armpits or something? By now the head of my straining cock was poking out the top of my boxers and I don't think I could of been any hornier. When I got to the shower door she opened it wide and said "You may as well get in here. You have seen it all already and now I can see yours!!" I looked down at my cock sticking out over my shorts and without replying slowly removed them along with my singlet and stepped into the shower. I handed her my razor and closed the door behind me. I couldn't believe I was standing just centimeters from my naked sister-in-law. We shuffled around so I could get some of the water and she started to lather up her pussy again. As I stood staring at her, she proceeded to shave herself bare. It was almost too much for me and I nearly came just at the view!! When she finished, she moved closer to reach behind me and put the razor on the little shelf. Her erect nipples came into contact with my chest and then I felt my cock touch her stomach. She stepped back and looked down at my hard cock. "Turn around and hand me the soap" she whispered in a voice that was only just audible. I did so and she started washing my shoulders and back. Slowly her hands moved down to my arse, then started moving round my hips and along the bottom of my stomach. Her tits were crushing against my back and her right hand grabbed hold of my shaft and started to rub. A groan escaped my lips followed by a moan from Karen as she started stroking my cock into a frenzy. I knew I wouldn't last long but also knew that I may never get a chance like this again. I reached behind me and placed my hand right between my sister-in-law's slightly parted legs. She moaned again as my fingers started to caress her pussy and then bit lightly on my shoulder. My head was spinning and I groaned that i was going to cum. She stroked faster as I erupted all over her hand and the shower floor. I kept caressing her pussy and as my orgasm subsided I felt her body tense up as she launched into one of her own. I kept stroking her clit until she pulled my hand from her quivering pussy. I turned to face her slowly and as I did she hugged me close. Whispering "Thank you" as our bodies locked together, my cock was still hard as steel, pressing against her belly. "You're still so hard?" she said pushing herself against me. "Well you seem to have that effect" I whispered back letting my hands fall down her back to her arse. I puller her closer again, crushing her breasts into my chest and she moaned "Oh Fuck..." right in my ear. My horniness at an all time high I said, "Do you want to add a "me" to the end of that?" Karen didn't say anything and I thought maybe I'd pushed it a bit too far, but only until she slowly lent back against the wall, lifting one leg up and planting her foot on the wall behind us. "Me" she said with the sexiest grin i had ever seen. She grabbed my cock, pulled me towards her and slid it straight inside her soaking pussy. She let out a long sweet moan saying "Oh god yes, fuck me!!" I started pumping slowly in and out of her and she leaned back arching her hips towards me. I was in heaven and we kept fucking until the hot water had run out. I quickly turned the taps off and we jumped out of the shower. I lifted her arse up onto the bathroom sink and as I stood between her open thighs, she looked right into my eyes and said "Come on old man, fuck your little sister-in-law's pussy..." I needed no further invitation and started thrusting deep and hard into her. "Harder" she said breathlessly, "Fuck it harder..." She was now nearly screaming. I held her hips and started fucking her as hard as I could until her body went into mad spasms of ecstasy. This in turn sent me over the edge again and I unloaded deep inside her. Collapsing against her, our chests heaving in time, I let out a little laugh. She asked me, "What are you laughing at?" I told her "Oh, nothing really..." What I'd actually been thinking about was lying in bed tonight and telling Ellen, "I've been a naughty boy..."