I have 2 female Boston terriers. They are both less than two years old. My husband is wanting a mastiff but I am worried. I have never had a big dog and I am worried that a big dog might hurt my little bostons. One of my girls (Allie) is very possessive of all of the toys and wants all the attention. She was here first. I have read that you shouldn't have 2 dominant females. Maci is pretty submissive, so there aren't usually any problems. They do occassionally nip at each other. My concern is that Allie might get snippy with a big dog and get hurt. We would probably get a male because of Allie being so dominant. Could there still be issues of dominance even with a male dog? Does anyone have any suggestions or experience with mastiff's? We have researched the breed and they seem like good family dogs. Any advice or insight would be appreciated. Sorry for the long post.