I came home from school early one day and caught my stepmom (Mary) fucking our Black lab Duke. Ã‚Â Now I had been suspicous that she had been fooling around with Duke for awhile. Duke walked arouind with a semi boner most of the time with about 3-4 inch's of his red penis sticking out of his sheath. A couple of times I had walked in and found Duke with a full blown erection while he was licking a pair ofÃ‚Â Mary's soiledÃ‚Â panties. Let me stop for a minute and describe Mary. She is 5'7",about 135 pounds and her measurments are 38DD-26-36 and she has a fantastic ass. I had seen her nude a bunch of times as sheÃ‚Â sleeps nude and is a very hard sleeper. She has a pretty pink pussy with large fat lips that look like a butterflys spread wings and she has a large clitoris that is about a half inch long. ItÃ‚Â is the size of your pinky finger.Ã‚Â She shaves itÃ‚Â so there is no hair on it.Ã‚Â Anyway when I got after Duke about licking her panties she laughed it off and said he is just a dog after the scent of my sex. But I also noticed that her nipples were hard when she saw him licking her panties. Another time I came home from school and when I couldntÃ‚Â find Duke,Ã‚Â I went up stairs and whenÃ‚Â I called his name I heard him barking in Marys room.Ã‚Â WhenÃ‚Â I tried to open her door she said just a minute. After a few minutes she opened the door and she was all flushed and was wearing just her dressing gown. She was sweating and the gown was clinging to her and I could see her all of her hard nipples including the areolas and her pussy lip's.Ã‚Â When I didnt see Duke i asked her where he was and she said I had to let him out on the deck because he was getting wild. I went out the french doors in her room to the deck andÃ‚Â I saw Duke sitting under the tree licking his penis. I went down and called to him and as he came to me I saw he hadÃ‚Â an erection and it was flopping around as he ran. Now Duke has a huge cock,I measured it one day just to see how long it is,and its 10 1/2 inch's long!! At the knot it's the size of a lemon. I was used to him having a boner,but when he sat down I could see that his muzzle was wet. I reached over and rubbed my finger on his muzzle and smelled my finger. I didnt know what it was but it smelled real good and it made my penis start to get hard. I went back in the house to talk to Mary and found that she was asleep in her room. She was lying on her back with her legs spread and her pussy was wet and swollen and all of a sudden Duke ran by me and started to lick her cunt. Mary opened her eyes with a start and said Oh my goodness what are you doing and tried to push Duke off. I had to work real hard to get Duke off,but I finally pulled him loose. Mary pulled the sheet over herself andÃ‚Â I led Duke outside. It was only after we got outside that I realized that I had a huge erection. I was so hard that it hurt and I rushed to the bathroom to jack off. NowÃ‚Â I dont have the biggest penis in the world but I haveÃ‚Â a nice thick 8" cock when its hard and the best feature is that it has a hugeÃ‚Â over size head.Ã‚Â I also take after my father and have large ball's that hang low in my sack. AsÃ‚Â I was jacking off all I could picture was Duke's big tongue splitting Mary's pussy lips. I came with such a rush that I saw star's,and sprayed my sperm all over the glass shower door's, I had never in my life came that hard or that much in my 16 year's. What a mess it took me at least 10 minutes to get it all cleaned up. After that day I began to watch Mary around Duke. And I saw that on ocasion that Duke would walk up and stick his nose under her nightgown or her dress and give her a quick lick. Mary would always push him away and scold himÃ‚Â but he would come back and try again. One dayÃ‚Â I came home from school and Duke was sleeping on my bed and asÃ‚Â usual his penis was sticking out of his sheath. I wouldnt have paid attention,but his sheath was wet and kind of crusty looking. I rubbed my finger over it and it was sticky but kind of oily and it smelled just like what was on his muzzle before. Now I have to admitÃ‚Â I now know what this smell was sinceÃ‚Â I had borrowed a pair of Marys dirty panties to jack off with,it was pussy juice.Ã‚Â It hit me like a bolt of lightening,the only way that pussy juice could get on his sheath was that it had been in Mary's pussy. Once again i had a boner andÃ‚Â I ran to take care of it. AfterÃ‚Â I cleaned upÃ‚Â I had to think how canÃ‚Â i catch her and Duke. I knew that Mary was a late sleeper and that she was fucking Duke whileÃ‚Â I was in school. About a week later we got sent home early from school and thats whenÃ‚Â I caught her and Duke fucking. I walked in and as soon as I got upstairsÃ‚Â I heard Mary moaning and telling Duke to fuck her hard. I pushed open her doorÃ‚Â and there she was on her hand's and knee'sÃ‚Â and Duke wasÃ‚Â buired up to his balls in her pussy. I was shocked that she could take his love knot inside her cunt. It was later thatÃ‚Â I found out that it took awhile for to get it inside her pussy.Ã‚Â Once it was inside her pussy it swelled to its full size and she couldnt get loose and they were stuck together. Mary didnt even notice me as she was coming like gangbuster's. I took off my cloths and my penis was harder than it had ever been and the viens were sticking out. I stood there for a minute or two and just watched Duke take her pussy. Mary was just along for the ride as Duke fucked her like a bitch. AsÃ‚Â I watched she came at least 6 time's and Duke started to fill her pussy with his sperm.Ã‚Â Even though they were stuck together and Duke's knot was acting like a plug,his sperm started to drip out of her pussy and run down her legs. Marys pussy lip's were stretchedÃ‚Â so big that they looked like they were going to fly off. I couldnt help myself I reached under Mary and cupped her left breast and pinched her nipple. Mary slowly turned her head as if she was in a trance, and when she saw me her eyes got real big. As she tried to speak she started to cry and say oh my god what are you doing here? As she said this she still was pumping her pussy against Dukes penis. I sauid we got out early from school. I knew that i had her whereÃ‚Â I wanted and that she was going to fuck and suck me whenÃ‚Â I wanted it. Just to make sureÃ‚Â I ran and got my digital camera. I took a bunch of close up's of her pussy so I got the dog's penis and her swollen pussy lip's. I also took some so thatÃ‚Â I got her face in the pictures. I ran to my room and downloaded them on my computer.Ã‚Â After almost 45 minute's Duke finally pulled his penis out of her pussy with a wet sucking noise. I was amazed at the size of it,it was bigger than normal and I still dont know how Mary took his huge love knot in her pussy. Duke's sperm was running out of her pussy like a waterfall,it looked like a quaret of spermÃ‚Â and Mary was still shuddering from her last orgasm. I had to fuck herÃ‚Â I couldnt help myself,soÃ‚Â I pushed her butt up a little higher and I shoved it into her cunt. Her pussy was a little bit loose butÃ‚Â I didnt careÃ‚Â I startes driving my penis in as far asÃ‚Â I could. At first Mary didnt say or do anything but then she started to fuck me back. i wish i could say thatÃ‚Â I lasted a long time,butÃ‚Â I was so turned on that after about 5 minutes I shot my nuts in her pussy. After I pulled outÃ‚Â I lay next to her and cuddled her as she sobbed,I cant believe you caught me fucking your dog. I told her thatÃ‚Â I wouldnt tell anyone as long as she gave me pussy when I wanted it. She reached down and squeezed my penis and said really? I told her that it was the sexiest thing I had ever saw. Even as we talkedÃ‚Â I started to get another erection and I rolled over and started to play with her big titt's. Mary said wow are you ready to go all ready? I said with titt's like your's and your pretty pussy oh yeah Im ready and I got on top of her. Mary reached down and put the head in her pussy.Ã‚Â SheÃ‚Â said wow if I knew you had a big dick like this maybeÃ‚Â I wouldnt have started to fuck Duke. As we slowly fuckedÃ‚Â I asked her how she got started to fuck Duke. She said that her and my dad were not fucking anymore and she was pretty sure that he had a girl friend. So one night when she was masturbaiting Duke jumped up on the bed and started to lick her pussy. At first she tried to push him away,but he kept at it so she figured he wasnt hurting her so what the hell. She decided to fuck him when she saw the size of his penis. She got on her hands and knee's and Duke jumped up on her butt and tried to shove it in. She had to reach back and guide him into her cunt,but after he felt the wet heat of her pussy he just slid it in her hole.Ã‚Â He went into her all the way up to his knot and when he tried to put that in she held his so he couldnt go in. I asked her when did you let him go in you? She said she went on line and read that if you let him go in before he swells up real large it wont hurt as much. So she did it that way and it still hurt but not real bad. And that's how she was fucking him ever since. From that day on we have been fucking ever since. Mary divorced my Dad after he got caught with a under age girl and she is fixed for life with her settlement. Me and Duke take care of her pussy and she has brought other women into the house that we get to fuck. Mary has a big imagination and we have expanded our fucking to include other dog's and various animals,but that is another story. I will write about that later.