When you finally make it to the Royal Library up near Sniflheim, you will be able to get this pastword. Upon going from the first floor to the second, you will find the yellow Tockle with it on the staircase.
Upon choosing this option at the Altar of Reverie, you will be in Alltrades Abbey, a location all too familiar with longtime players of the Dragon Quest franchise. While there are some people there looking for a change in vocation, the place has had a recent influx of older males seeking a change into a bunny girl. Speak to the NPC on the throne to learn of their plight, with him hearing of a book that might teach the ways of the bunny girl. He will give you the quest, Fogies Just Wanna Have Fun, and sets you on your way.
In order to get the item needed for this, you will have to return to the normal world. Once you do, Zoom over to L’Academie de Notre Maitre des Medailles and head inside the main building. Go into the library at the back of the first floor and look for the golden sparklie on the ground, which will net you The Bunny Girl’s Bible. Bring this back to the NPC at Alltrades Abbey to finish and be awarded with the Golden Pickaxe. This item basically gives you an extra item whenever you go to a mineral node (the ones that give three items). It doesn’t seem to be set in stone, though, as the item you receive is randomly selected from a set pool.