mosh tail 

A dogs tail wagging in a circular motion, much like a moshing speed metal freak

Hey, check out out that Shi-Poo doing the mosh tail.

mosh tail by Schwinkmartindale July 6, 2008

Mosh Tail 

The act of purposely or accidentally grinding, grabbing ass, or groping in any way at a concert; mainly in the mosh where it is easy to get away with it

Person 1: Dude how was the concert last saturday?

Person 2: It was epic, l was grinding up against this really hot chick

Person 1: Sounds like you got some pretty awesome mosh tail

Mosh Tail by Synyster101 June 20, 2011