The Collaborative International Dictionary of English v.0.48:

condog \con*dog"\ (?; 115), v. i. [A punning corruption of
   concur.]
   To concur; to agree. [Burlesque]
   [1913 Webster]

   Note: This word appears in early dictionaries as a synonym
         for the word agree; thus. "Agree; concurre, cohere,
         condog, condescend." --Cockeram.
         [1913 Webster]