I may be wrong, but I think what Sherwin may be experiencing is reverese sneezing. It is common in small dogs and it is caused by an inflamation in the soft palate (on the roof of their mouths). The fact that you say breathing into his nose seems to help is what makes me think it could be reverse sneezing. My first dog used to have reverse sneezing attacks, and holding her head up and rubbing her neck would help, a friend of mine does what you do for her chihuahua. Apparently the key is to get air flowing through the mouth/airways of the dog to reduce the inflamation. I don't want to discourage you from going to the doctor, it is always best to make sure that your dog isn't suffering from any serious problems.