When I was married as my wife was very close to her family we used to visit her parents house nearly every weekend and some times we stayed in the guest bedroom which was next to her 18 year old sister Lisa who always walked around the house in hardly any clothes and knew she was sexy and and many times I would go into the bathroom and jerk off which ened up with me sometimes shooting my spunk across the room.On the sunday Debbie,my wife stuck her head round the bedroom door and said she was going shopping with her parents and would eat out so she told me to behave and look after Lisa and she was gone.I lay in the bed and threw back the covers and beagn to wank my cock thinking of Lisa riding me and then I heard loud music so I went over to the window and saw Lisa laying on the sunbed in a skimpy bikini soaking up the sun and I picked out some shorts and went downstairs and said good morning and I didn't bother to hide my hard cock which was sticking out the front of my shorts as I said how good she looked.She smiled and asked me to bring a couple of beers outside and she closed her eyes so I crept out and without her hearing me put a cold beer on her belly and unbeknown to me she had undone her top and her fell off exposing her large tits with fully erect nipples and I just stood looking at those beauties and Lisa held her arms to them and said I was naughty,but with a smile.She put the top back on and guzzled her beer and said she had a real thirst on today and then she looked down at the bulge in my shorts and asked if she had caused that so I told her I always get hard when she is dressed so skimpingly around me and she placed her hand over my shorts and began to rub it and then she took hold of it and led me upstairs into her parents room and undid her top and yanked down her bottoms to reveal a smooth pussy and she soon whipped my shorts off and started to gobble my prick like a pro and I knew she had been fucking for the last couple of years and it showed as she moaned and groned as I told her what a whore she was and I told her I want her to ride me so I can suckle on her tits and soon she was bouncing up and down as her tits wobbled around and she was like a foul mouthed bitch as she told me to shoot my seed into her to make her pregnant so she could get one back on her sister and she was a much better fuck than her sister ever would be and I noticed the window was open so anyone would be able to hear but I was too far gone to care and I grabbed her arse as I knew I would come and my spunk shot into her young pussy and so much shot out it spilled onto her parents sheets as I pusehd her down and carried on fucking her as he legs were wrapped round my back.This was the start of our releationship and it ended up with her giving birth to a bouncing baby boy and I divoreced her sister and we married two years later.Now we have 3 kids and have joined a swinging club where we meet and bed females(she doesn't want any other men)one of which may move into our home as our own nanny and livein sextoy for either of use to play with as and when needed.The details have neraly been agreed by way of contract.