Green’s Dictionary of Slang

dancing dog n.

[SE dancing + SE dog/dog n.2 (1b); the term was used in a period when dancing was no longer seen as fashionable]

a man who enjoys dancing.

Show quotations
[UK]Daily News 27 Mar. in Ware (1909) 104/1: Then drop in those supercilious masters of the situation, the dancing young men, the ‘dancing dogs’, as they have been called.