Prepping for Training
To prepare for this, you will first want to have a designated 'time out' area for your Pomeranian. During certain points of training for aggression, this is a 'must', so you will need to have this before you start.
An indoor canine playpen like the IRIS 24'' 4-Panel Pet Playpen with Door
often works best; though blocking off a section of a room with gates may work as well. You will want the chosen area to be near the rest of the family and not isolated away from things. The kitchen or living room is often a good choice.
#1 Teaching Proper Hierarchy
Barring any health issues, or deep-set reasons for aggression such as past abuse, most Pomeranians that are aggressive toward a family member lack an understanding of proper hierarchy.
And for those showing aggression towards visitors to the home, but not listening to their owners commands to stop, are most likely also not understanding proper hierarchy.
In the canine world, within the den (house) where the pack (family) resides, there is a leader(s) (Alphas) and all other members of the pack are the followers (Betas).
The betas respect the alpha, rely on the leader for food (which a dog understands to be the very means of his survival), and would never be disrespectful to him or her.
So, growling, nipping at, or otherwise acting aggressive toward a human means that the Pomeranian is not seeing that person as his leader. He may see them as his peer, or even lower.
Therefore, teaching a dog all about who is in charge can often lead to a reversal of behavior.
There are 3 basic parts to this:
A 'Sit' must first be obeyed any time that food is given. This includes both meals and snacks.
When leaving the house or coming back in, all humans go first, followed by the dog.
In cases of severe aggression, humans are always at a higher physical level than the offending dog. This means that at all times until the problem is fixed, humans do not sit on the floor with the dog. And the dog is not allowed to be up on the sofas or on their human's beds.
#2 Your Immediate Reaction
Any time that your Pomeranian makes an aggressive action, he should immediately be placed in his time-out area as mentioned earlier.
Going back to how canines perceive their world, if someone in the pack (family) commits a serious enough offensive, they are banished from the pack.
So, the idea of this is to make a very strong statement that banishment is indeed on the table.
During the time-out, it is very important that no one speaks to the Pom, or even look at him. It can take puppies or dogs anywhere from 2 minutes to 15 to realize that they are being ignored. When you believe that he has realized this, wait another 5 minutes.
#3 Slow Introduction Back
Once the Pomeranian has realized that he is being banished (at least temporarily), he can be let out and placed in the exact same situation as before when he acted out. For example, if he was in the living room and had nipped at someone's ankles, place him there and have that person walk across the room again.
If at any time he acts aggressive again, he is immediately given a time-out again.
If he does not act out, he is spoken to, but not petted or played with.
If he continues to act appropriately, he may be petted or even given a treat after another 5 to 10 minutes.
You may find that you need to repeat the time-outs quite a bit. It can take days of this for a dog to really start to understand that his aggressive behavior will not be tolerated. And, this must all be done in conjunction with the other steps of how the food is given, how everyone enters and exits the house, and how others place themselves in relation to the dog.