verb/keˌdaɾ ˌkomo kaˌɡant͡ʃo en alˈmaɡɾo/
to make a show of oneself
It refers to Joaquín Rodríguez Ortega, nicknamed Cagancho, a famous bullfighter in the 1920s, who, in Almagro, Ciudad Real, had one bullfight of such poor quality that the public threw things onto the bullpen and he had to be escorted out under police escort.