Dog biting other dod

Question
I have 2 male Shih Tzus. Coco is 2 years old and Max, 6 months. Neither have been neutered yet. Suddenly, Coco is all over Max...humping him, and biting and scratching him to the point where little Max has a sore, raw place on his side.  I've done everything I can think of to get him to stop, but nothing is working. The plans have been to have Coco neutered, but just haven't been able to yet. How long should I expect Coco's behavior to last, and will having the older dog neutered stop this behavior? Thanks for any help you can give.

Answer
Coco is actually just showing pack behavior and being dominant over the new puppy.  This usually last until the new puppy submits completely and the older one is satisfied that the newbie gets the point (about 1-2 weeks) but if Coco is very aggressive I would say that he may need to be separated from Max until you can get him neutered so he does not hurt Max too bad and neutering will calm his behavior some and the rest will be time and training.  Hope this helps and good luck