A Spunch is a collection of people (sometimes in a club, society etc.) with a common interest, passion or obsession.
A Spunch Dog is the designated leader of a club or society. If, however, a group is less official, the Spunch Dog thereof is the person most enthusiastic about (or well-versed in) the field of choice.
Sorry I'm late, I was getting a coffee and the local Caffeine Spunch was in. Their Spunch Dog is awesome but they made the cue way too long.