It was two-forty in the afternoon, and my wife was just about to leave to pick our daughter up from school, when my phone made that familiar "ding" sound of a message coming in. I work from home on Fridays, so assuming it was work I just casually picked up my phone as my wife put on her coat. "I'm fucking myself right now. I need your cock!" it read. "Who is it?" My wife asked. It was from my mother-in-law. I stammered slightly. "Uh... just work love, I'll reply in a minute" I hated lying to her, but somehow it seemed preferable to explaining that I'd been fucking her mum for almost a year. No sooner had the words left my mouth than there was another ding. The phone was still in my hand. "I'm at the end of the road. I'm so wet!" At this point it probably goes without saying, but my mother-in-law is amazing. She's sixty-two, but she doesn't look a day over forty-five, and she's gorgeous. Her body is fantastic, and she always manages to dress in a way which shows off her body but looks classy and tasteful. Oh, and let's not forget that right now she was obviously sat in her car at the end of my street, fingering her pussy, waiting for my wife to leave so that we could fuck. My mind wandered to a vision of her sat in the driving seat of her mercedes getting herself off. "Something urgent?" my wife asked, jolting me out of my trance. "Nothing that can't wait for me to kiss you goodbye" I said, kissing her on the lips. At least that was the truth. "Back soon" she said with a smile, and she walked out of the door closing it behind her. I stood in the hallway, watching through the frosted glass of the front door, as she got into the car and then pulled out of the driveway. My cock was hardening in my jeans, so I grabbed my phone from my pocket to give my dirty slut of a mother-in-law the all clear, but before I could even unlock the phone her car appeared on the driveway. Okay, the glass is frosted, so technically I didn't know it was her, but the car was the right colour and it would be a pretty unlucky coincidence if it was anyone else. I suppose you’d say I'm having an affair with her, although I don't really see it that way. She is married and loves her husband. I am married and I love my wife (her daughter). But, neither of us has the sex life we want in our respective relationships. We aren't in love, we don't long to just spend time together, we aren't ever going to consider leaving our respective others and running off into the sunset. We just fuck. And fuck. And fuck. Every chance we get. But, as you can imagine, those chances are still relatively few and far between, and by the time we get the opportunity we're desperate for each other, so it's usually very passionate. There's a lot of groping, kissing, and exploring each other's bodies before we start the real sex. Today was different. As with most mother-in-laws, she has a key to our house, so she just let herself in. As soon as she had closed the front door behind her she rushed towards me, but just as I went to pull her to me to kiss her she dropped straight to her knees and started attacking my belt buckle. Within moments my belt was undone, the button of my jeans was open, and she was pulling down my zipper. She grabbed the waistbands of my jeans and boxers at the same time, and pulled them down just far enough to let my now almost fully erect cock spring free, taking it straight into her mouth and sucking it hungrily. She started teasing my balls with her left hand, and wrapped her right hand around the base of my cock, jacking it in time with sliding me in and out of her mouth, all the time looking up into my eyes. She grabbed my ass with both hands, pushed her tongue all of the way out, and forced my cock as far as she could into the back of her throat, using the tip of her tongue to lick my balls. "Oh FUCK!" I moaned out. It was the first thing either of us had said since she came through the door. Damn, I love it when she sucks my cock. I mean, everyone loves a blowjob, but looking down into your hot mother-in-law's 'come fuck me' eyes as she chokes on your cock is tough to beat. The blowjob didn't last long though. She sucked me just long enough to make sure I was as hard as I was going to get, then she stood, turned around, bent over, and lifted her dress up over her incredible ass. Starting an her high heels, I scanned upwards taking in her shapely, stockinged legs to her suspended belt. Mmmm, no pants, and her pussy was glistening. Damn my mother-in-law was a whore! I was instinctively stroking my saliva-covered cock as I took in the view of her body, when she looked back at me over her shoulder "Don't just stand there" she said. "Fuck me!" I didn't need to be told twice. I positioned the head of my cock so that I was barely touching her pussy lips, and given that she was so wet, grabbed her by the hips with both hands and literally slammed my cock all of the way into her in one hard, fast movement "Uugghh!" she moaned loudly as I drove all of the air from her lungs, "Yes!" It was clear what she wanted, so I skipped the usual slow start and immediately starting fucking her hard and fast. "Harder!" she shouted. "Deeper! FUCK ME!!" The tone in her voice was unusual for her. It was an interesting mixture of a barked order and frustration. As hard as I thought I was giving it to her, I obviously wasn't hitting the mark, and she obviously wasn't in the mood for a gradual build up. Keeping my left hand on her hip, I moved my right hand and firmly grabbed the back of her neck. I pushed down to bend her over more, and at the same time kicked her legs further apart with my foot. The combination of the those gave me the depth I needed, and I used the extra traction I had from holding onto her neck to fuck her even harder. "Oh FUCK!" she screamed, "Yes! Yes!! YES!!!" She had obviously held herself on edge in the car, denying herself release, because I had only been fucking her for about ten seconds when I felt her entire body start to shake. "Fuck! Yes!! YES!!! Ugh!!" The intensity of her orgasms is always a sight to behold. When she really cums, her entire body shakes and she loses the ability to actually form words. "Uggh!!! Aaahhh!! Uggghhh!!" she groaned as her orgasm hit its peak. I kept up the pace as I felt the juice from her pussy running onto my balls. As her breathing calmed down, I didn't stop, but I slowed my pace to give her a chance to recover. But, again, that wasn't what she wanted today. I had seen her dying to fuck before, but I had never seen her like this. She began humping herself back onto my cock. "More!" she said. "I want your cum! I want your cum in me before she gets back!" Did I mention that my mother-in-law was a dirty whore? "Give it to me!" she said. "I want to talk to her. Uuggh." - honestly, I was confused for a moment. "I want to talk to her when she gets back. I want to feel your cum dripping out of me as I talk to my little girl" Holy fuck! A thousand thoughts ran through my head at once. How good her body looked impaled on my cock. How good her pussy felt. I thought about how hot it would be watching my wife talk to her mum, knowing that my cum was literally dribbling onto her thigh as she did it. Not only did the idea of it turn me on, but the idea had made her so horny that she had engineered a situation to allow it to happen. I lost control. I wrapped both of my hands around her neck, still allowing her to breath, and ruthlessly began fucking her with everything I had. It was my turn to moan now. "Oh FUCK! You like that?? You like that you dirty fucking slut? Oh FUCK!!!" "Yes! I love it! I love your cock! Give it me! YES!!!" She knew that I was gone. My wife could have pulled up on the driveway at that moment, and there’s a good chance I wouldn’t have been able to stop. I wasn't going to last long in this state, and she knew it. She reached between her legs and started rubbing her clit. I could feel her fingertips brushing against my cock as I continued fucking her. "Holy FUCK!!" I yelled. "Yes!! Oh FUCK!! You're such a dirty whore. FUCK! I love this pussy!" "Yes!!! FUCK ME!!! Don't Stop!" she screamed. "Fuck my pussy! Fuck your pussy!! This is YOUR pussy!! I'm your whore! Give it to me!!" I felt my balls start to tighten. I could feel that awesome sensation you get in the head of your cock when you're about to let go. I found another gear and sped up. "OH FUCK!!!" I moaned out "FFUUCCCKKKK!!" She started rubbing her clit harder and I felt her body start to shake as the first wad of cum erupted from the head of my cock. "FUUCCKKKK!!! YES!!!" I could feel my legs trying to crumple under me with the intensity of my orgasm, so leaned forward over her slightly to keep myself upright, and kept pounding into her as I continued dumping cum into her wanton cunt. I think feeling my cum filling her sent her over the edge "Yes!! Yes!!! Give it me!! Fill me up!!! Uugh! Uggh! Arrgghh!! Uuuhhhh!!!" I kept pounding into her until we'd both come down from our orgasms, then slumped over her, my hips still reflexively sliding my cock in and out of her slowly as I started to soften. She did what she always does after we fuck, and turned around to suck my cock clean, but I stopped her. "You can't" I said. "Not today. She'll smell it on your breath" I knelt down to bring my head level with hers and kissed her deeply instead, exploring every inch of the inside of her mouth with my tongue. "That was incredible" I said to her once we broke off our kiss. She was just about to reply when my wife's car pulled onto the driveway. We both got up quickly and she pulled down her dress and adjusted her hair as I quickly put my juice-covered cock away and did up my jeans. My wife came through the door moments later. "Hiya mum!" she said. "Hi darling!" her mum said, as she gave her a hug and a quick peck on the lips, then flashed me a sly smile. Did I mention that my mother-in-law is amazing?