Double teaming family dog

So back when I was 14, I went through a big experimenting phase that ended up including my step brother. He was 12 at the time and I found out that our family female border collie would lick peanut butter off of my dick. I did it so much that I ended up training our dog to give blow jobs. The next time it was just the two of us at the house, after we did our experimenting I showed him. He wanted to try it, so while he was getting head from the dog I decided to try and fuck her. She let me and I fucked her for a bit then me and my step brother switched. After a bit he stopped because he didn’t want to finish in her, so I fucked her again while he masturbated while watching. I came in her and had her lick me clean. For a while it became another one of mine and my step brothers things to do when we were home alone. She loved getting fucked by us, when I would come home from school she would run up to me and just roll over for me.