Back in the days (90´s), in american football matches in México, fans use to shout "Ehhh Pum" during the kickoff, this in support of their own team. Then, in 2003, Atlas (football soccer) fans change the sound "Pum" for an offensive word) to use it when the rival goal keeper kick the ball. This way of insulting the rival goalkeeper gain very quickly big popularity all across Mexican stadiums.,In this case, Pachuca´s fans, having fun, replace the offensive word with "Tuzos", this to support in a funny way their own team
Lyrics
Ehhh, Tuzos! Ehhh, Tuzos!... (Repeated...)