My Das’s Girlfriend

This story contains graphic sex with animals. If you are not into that kind of thing DO NOT READ ANY FURTHER.

I am 18 years old. I live with my father and his girlfriend in a four bedroom house.
So it was an average day. Me sitting on my bed watching tv. I was watching CSI. And out of the blue, I started getting horny. So I checked to see where my dads girlfriend was. I could tell that she was in her room, cause the door was closed and I could her the tv in the room. So I closed my door. I put a DVD in the player and turned it on. It was called Mouth Watering Melons. I pulled off my pants, and laid down on my bed. I turned it to the scene with Britney Skye. I started jacking off my cock as I watched the scene.
Now let me describe myself for you. I am 6′ 1″ and 165 lbs. And I am athetically built. I have a 8 inch dick, with the thickness of 6.5 inches.
Now when I masterbate, I sometimes close my eyes and picture having sex with either people I’ve already fucked or other people. This time I decided to imagine fucking my dads girlfriend. Her name is Trish. She is 5′ 9″ and weighs maybe 140lbs. She is 49 years old. She had 38DD tits. And a nice big round ass.
As I laid there imagining fucking her. I heard a loud thud. I paused the movie. And put on my pants, trying to hide my rock hard dick. I stepped out of my room, and what I heard surprised me. I could hear Trish moaning in her and my dads room. This made my balls tingle. I wanted to see what she was doing so bad. Than I remembered that her and my dad never closed the blinds in their room. I went into the backyard and slowly crept to the window. I looked into the room, and what I saw shocked me beyond belief. I was expecting to either see her fucking my dad or have a dildo inside of her. And I knew my dad wasn’t home, so it had to be a dildo. But it was far from a dildo. Trish was on her knees on the ground. And behind her was Duke. Her 4 year old labrador retriever. She was getting fucked in her pussy by her dog. And to make it even more extreme. She was sucking her 3 year old German Shepard, Bullseyes cock. I couldn’t believe I was seeing this. She was fucking and sucking her dogs cocks.
Now me I am an extremely kinky person and beastiality turns me on. I went back into the house and was thinking of a way that I could walk in on her while fucking the dogs.