So my SIL and I would meet in various shopping out of town retail parks, you know the type with the usual stores in them and she would jump in my car and lie down on the back seat, whilst I drove her to my house. Wife was at work so knew she wouldn't be home. Once I arrived at the house, the usual approach would be for me to reverse the car up the drive towards the back of the house. I'd enter the house and then open the back door to the house, open eh back door to the car and the SIL would then dash the short distance to the house. Doing it this way shielded us from the neighbours who were mostly elderly and retired, so didn't want them seeing anything. On this occasion, once we were inside the house we went upstairs and into the spare bedroom. We immediately started to kiss each other and rub each other’s bodies, working each other up to. frenzy. Eventually we started to undress and were able to take our time as we thought there was no chance of us being disturbed. Once naked we moved under the duvet where it was nice and warm and continued to play with one another. She would rub my cock and play with my balls intermittently as I rubbed her pussy, fingered her and sucked on her titties. She had a good-sized set of boobs, not too large but not small either and they sat upright without any assistance when her bra was a off. So there we were getting into it and I asked her to suck my cock, which she never refused to do for me. She ducked her head under the covers and was going to town on me, sucking me and stroking me, it was great. After about four or five minutes, I pulled her up from under the duvet and kissed her, sharing tongues and saliva with one another. I then told her to sit on my face. Now I knew from experience that this was not something that she did on a regular basis, however on this occasion I managed to goad her into it. She shuffled up the bed and rested her thighs either side of my head. She grabbed the headboard and then proceeded to lower her pussy onto my waiting tongue. I absolutely went for it and was holding onto her thighs and forcing my tongue up into her pussy as much as I could, working back and forth on her clit and tunnel. All of a sudden, the doorbell went and we jumped out of bed in a panic, saying what the fuck do we do. I went over to the window and sneezed a peek out and couldn't see anyone at the front door downstairs as the roof shielded the view. Again, the doorbell went and I just stood there watching. Eventually after another 45 seconds or so the individual who was at the front door began walking down the path, it was some door to door salesman, probably selling guttering or windows. A huge sigh of relief and the after calming the SIL down, we removed her clothes again as she'd gotten dressed during the commotion. Not to say that my cock and lost its hardness as well, lol. We went back under the covers and lay in each other’s arms talking, caressing each other getting back in the mood. I then asked what she wanted and the response I got was "I want you in me". So, with very little ceremony, I slipped between her legs and she took hold of me and rubbed my cock head up and down the front of her pussy. After thirty odd seconds of this behaviour, I slid into her slowly so as not to hurt her. She had said previously that her husband was much smaller and she loved my bigger cock. Once I was in deep, I slowly lay there embedded in her tight pussy and then eventually started to rock back and forth. Her legs wrapped up over my back and she pulled me into her. In order to ensure that she was getting satisfaction, I began to thrust into her harder, bottoming out in her tight cunt. She was a lady who when getting fucked like to moan and enjoy herself and she was pretty vocal when we were going at it. I was asked to fuck her harder and keep going, so I did just that. She eventually came, flushing on her chest as evidence that this was the case but I hadn't reached my climax yet so asked her to turn over so I could fuck her doggy. She asked me to be careful as it goes deeper in this position, so I entered her again and grabbed her hips so that I could pull her back onto me, as much as I could drive my cock into her pussy. We got into a good rhythm and carried on. like this for at least ten minutes. She asked me a couple of times if everything was okay as I had not come yet but I explained that I was enjoying it so much I was trying to hold on for as long as I could. In reality this was true, but it was just one of those occasions where it took me ages to come. Eventually I felt the pressure build and I knew that I was about to come and sped up, telling her that I was about to come. She pushed back onto me and told me to "fill her cunt up with my come". I loved when she spoke like this as my wife would never speak as filthy as the SIL, so it was kinda dirty and sexy to hear her when she spoke like this. Finally, I came in her and would love to say that I flooded her pussy with my come but with having the snip, everyone knows you don't produce a huge amount of liquid. I pulled out and looked at her puffy lips and was very tempted to drop down behind her and lick her ass and pussy but decided against it. We flopped down on the bed and lay entwined in each other’s arms, sweating, heartbeat racing. "God that was great she said. It has to be one of the best fucks I've had". I had to agree with her as it was absolutely incredible for me as well. The time spent that afternoon was superb. We didn't have any more sex, we lay for a bit speaking about meeting again and then got dressed, took her back to her car and dropped her off. That afternoon in the office had me walking about with a smile on my face for sure.