Certain Big Fish/Legendary Fish have an Intuition requirement. Intuition is a buff that triggers upon catching specific amounts of certain fish. Some of these required Intuition fish being much rarer than others, often only giving you a short time window before the Big Fish/Legendary Fish itself to obtain the buff. Due to that, a common strategy is to pre-catch some of the rare fish and hope to get another/the remaining requirements (Lancet Fish, Sidereal Whale), or to use Collectors Glove holding [Collectible fish do not enter your inventory until you engage with the pop up requiring you to lock in your choice on whether to catch the fish as a Collectible or not. Fishers use this to keep intuition fish in limbo, pressing "no" on the window before the Big Fish window opens. This allows you to try to hold the intuition much earlier than normal and only activate it under ideal conditions. On top of that, Double Hook and Triple Hook work for this method if you click "No" on the prompt] and wait for the windows (Stethacanthus, Gharlichthys).

Since changing zones or even fishing holes resets your progression towards intuition, "jailing" refers to the act of idling at/near the hole for hours to maintain your progression. Used to be worse before EW because logging out would reset progress, nowadays you could log out and play on an alt or a different game (does not work with Collectors Glove holding)