Okay so as some may know I still live at home. Well my mom has 2 yorkies, one girl(4) and one boy(5). The dogs all play together great but once in a while the yorkies get a little rough and I have to pull Corona away because shes still small and Im afraid they might hurt her. Also a little background the boy (5yrs) tends to get teritorial and growls and sometimes nips when he's sleeping and someone walks by or if he's playing with a certain toy and you get too close. Well Ive noticed that Corona is getting like this towards me when I pull her away from them. Is she picking up his habit? Or is she just trying to say "mommy let me fight my own battle". Maybe she doesnt understand Im trying to calm her down and shes just playing? If not will I have a chance to prevent her from developing his bad habit? Any advice would be more than great. I just dont want her to be a "bad" dog. And lets face it my moms boy Buster could get away with murder. (they try to repremand him but I think we're all pretty much afraid of him)  

P.S. Buster isnt THAT bad, just once in a great while. I think my mom just doesnt know how to prevent him from acting the way he does, so she just ignores it.  Plus if you try to get near him when he's in a mood he will draw blood. I will stop before I make him sound like a killer.