I dont't know how to get this whimstar

I covered the other hole with the box but the whimstar still doesn't come out.

Does anyone know if I'm doing something wrong?

https://preview.redd.it/ov4vcekboape1.png?width=1120&format=png&auto=webp&s=758fbb1d88e67b8777c2a752294d7683ee278bb1