Triumfantilism

A newly minted word meaning "the premature performance of a (verbal or even literal) "victory dance", where the term "premature" is usually meant in both senses of the word".  The phenomenon is not new, however, for example:

Example of usage - "Although we were somewhat amused when Tumorous11 began manically fisting the air immediately after making such a complete fool of himself, we also felt a sense of deep pity for him since he and his kind are always prone to such displays of counterproductive triumfantalism."