My grandparent's rottweiler does this. She also tries to grab your shoes in her mouth if you stop petting her and start walking away. Needless to say, she's not the most polite dog, but she LOVES to get attention. I would say it's a little demanding, as far as getting attention, but I don't think it's necessarily dominant. I definitely don't think it's breed specific either. I had a Saint Bernard and a golden retriever do this to me too.