You must go to the Miko shrine and find the Miko. There should be a box where you must pay 1000 yen to get the effect. I think to get to the shrine you have to go to snow world and interact with the tree that isn't snowy. You should be in a sunny grassy world with cicadas chirping in the backround. I think there are two poles where you must go between to get to the corn crops. The shrine should be near there. (Sorry if I got the directions wrong. It's been quite a while since I have played this game.)