I was attacked by a malinois last year. Police dog. I was simply putting him in a kennel and he exploded. I lost the end of my ring finger before I even knew he was attacking. Had on leather gloves an they weren’t even cut. Completely severed the finger with just pressure. He grazed the skin just over my femoral artery and grabbed my wrist on the way out of the kennel. I flung him off me and he attacked again so I protected my throat and face with my forearm. He shredded my forearm ,but I was able to fling him back the other way. When he came back that time , I slammed him in the face with the kennel door and kept doing so until he retreated.
As others have said ,use your body weight and any tools you can get hold of. I had a gun on my hip the whole time and the first opportunity I had to possibly use it was after it was over. If one ever attacks you ,you will be stunned how fast it happens.