Oops, it doesn't look like 'sooshu day' is a national day..

Other days

cat girl

Cat Girl Day
eat what you want

Eat What You Want Day
law

Law Day
slime

Slime Day
comfy

Comfy Day
self care

Self Care Day
hoodie

Hoodie Day
buddy

Buddy Day
boba

Boba Day
ask out your crush

Ask Out Your Crush Day