We have a 2 yr. old schnauzer that we've had since he was a pup. He is a pretty good dog and listens fairly well to me. My issue with him though is that while I am definitely the "master" (he only follows my commands and looks to me before making any moves) he seems overly protective of my children (ages 6, 7, 9). If we are wrestling around he tries to get in between us, will back up into them or on them and even jump up and lightly bite me! I'm not sure what to think about this... If I yell at him "NO!" a few times he backs off, but is still visibly worked up. What does this behavior mean? How do I correct it?

Any advice is much appreciated! Thanks!
Jen