The Crank-a-kai is a special machine that you can use to obtain items and even new Yokai. In order to use this machine, though, you will need special coins that can be acquired throughout the game, either from Requests, chests and even as rewards from Yokai Cam or Passwords. You will get the chance to first use the Crank-a-kai machine, which is the very same one where you first encountered Whisper, at the end of Chapter 2. You are only able to use the machine three times per day, after which, it will disappear and respawn at 6AM the following day (according to your system clock).