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

Other days

buddy

Buddy Day
nae nae

Nae Nae Day
boba

Boba Day
coffee

Coffee Day
slime

Slime Day
believe

Believe Day
my little pony

My Little Pony Day
book

Book Day
kiss a brunette

Kiss A Brunette Day
stud

Stud Day