It means to discharge the tension or release the pressure. Give free rein to passion or demonstrate feelings without qualms. Free yourself, let off steam. Release flames or fire. Allow a gas, fire, or smoke to be released by the vent.
1º_ Release a breath of fire. 2º_ For the previous one, show or externalize a passion. 3º_ Turn off the quicklime. It is formed with the prefix des- the verb fogar ("to do, to have fire").