My first time with my dog Bella

This all started about 1 year ago, I had just turned 18 years old and I was in my sexual prime. I was a toned kind of guy, short brown hair and about 5’9. Growin up I had always been around dogs, everyone in my family had one,but the story really begins about a year ago in December. My family had left after Christmas to go visit my stepmothers side of the family, I stayed back to take care of the Dogs and cat and watch over the house, I never really liked my stepmother anyways. So being home alone I of course had a girl over, we started fooling around and after a while she was on top of me riding my cock when all of a sudden i felt something licking my balls, I didnt notice my dog Bella coming into the room. She was about 8 in human years and was a black lab. I grew up with her and there she was licking my girlfriends sweet pussy juice off my balls. I immediately pushed her off, but she just kept coming back in and licking. My girlfriend unaware was riding me while we made out, So I just let it go, It felt great after all. It was unlike anything I have ever felt before, Bellas long warm tounge and my girlfriends hot wet pussy, I came harder than I ever have before, thrusting deep into my girlfriend, Bella had stopped and walked out of the room, My girlfriend got up and went into the shower to clean off.