The Root of the Behavior
Earlier versions of the Boston Terrier produced a dog of much greater substance and heft to enable him to be a worthy opponent in the dogfighting ring. History notes that the original Boston Terrier was not the cute little dog we know of today. Decades of careful breeding choices later produced Boston Terriers who were slighter of build, sweet-tempered, and amiable who thrived on companionship with their humans and other dogs. Boston is proud of their namesake son and has bestowed upon him several distinctions including a mascot position at the prestigious Boston University and the honor of being selected to represent Massachusetts as their chosen state dog. While there is nothing particular to the Boston Terrier that would make him predisposed to licking, it is a fairly common practice exhibited by many different breeds. There are a number of reasons that could explain this interesting canine phenomenon. From the time they are puppies, dogs lick as a means to communicate. Since dogs do not have a verbal language to express their needs, they quickly learn from observing other dogs to use their mouths to get what they want.
Encouraging the Behavior
Your Boston Terrier might simply be telling you that he understands his role in the family and yours as his wise and loving leader. Since dogs do respond exceptionally well to positive reinforcement, your Boston Terrier may be engaging in frequent licking behavior because you have inadvertently rewarded it. If Fido anxiously greets you at the door then jumps into your arms and lavishes your face with "kisses" and you show obvious delight, he will quickly learn that the behavior gained him his desired response. Because of this, you will see this type of activity again and again. If it is something that you find unpleasant or annoying, you can break this cycle by simply refusing to acknowledge Fido's attempts to engage you in this way. It will take some time, but eventually, Fido will realize that this is no longer the key to what he wants. Of course, there is also the option that you taste good. Dogs love the taste of salt, and undoubtedly, our skin tastes briny to them. No need to fear though; your Boston Terrier will not mistake you for McDonald's french fries and decide to turn the licking into a few hearty chomps. He just likes the taste of your skin; he doesn't want to eat it.
Other Solutions and Considerations
More commonly, Boston Terriers lick obsessively due to allergies. Allergies may find their source in food sensitivities or even autoimmune responses to environmental stimuli. Allergies can be extremely difficult to treat, and they must be managed in order for your Boston Terrier to enjoy a good quality of life. In rarer cases, some Boston Terriers do suffer from obsessive compulsive disorder, and the licking is a manifestation of that. Dogs in this state are not able to stop or regulate the behavior on their own due to a chemical imbalance in their system. They require veterinary intervention in the form of medication to help reduce anxieties to allow the dog to return to a state of mind where behavior modification training can be started. It is not an "either-or" type of plan. The medication simply levels the playing field, so the dog can respond to training methods.