Mooching is a legendary technique used by anglers across Vana'diel. It involves using live fish as bait to attract those more "finicky" big targets.
This key item increases the amount of time you have to land your catch when fishing with Drill Calamary or Dwarf Pugil bait. It does not function with any other bait/lure. The special bait and the key item are intended to be used together to catch Gugrusaurus and Lik for the Indomitable Spirit quest, but more experienced fishers will also find this useful when targeting Matsya.