I honestly don't think Couver realizes how small he is. When we go to the dog park, he acts like he's as big as the big dogs. If a big dog tries to take his ball, he gets upset and growls. He does not seem to react any differently to the size of the dog. He usually gets along with other dogs really well but if a dog gets in his business (stepping on him, won't leave him alone etc) he will sometimes nip. If another dog gets aggressive with him, he will not back down. This is something we are working on, but he is definitely not a submissive dog.
Khloe on the other hand, is very submissive and runs from most dogs. She has never really experienced confrontation because she is so little and I don't allow it
She is scared of big dogs especially and will usually hide between my legs and ask to be picked up.