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

Other days

cuddle up

Cuddle Up Day
get funky

Get Funky Day
lumpy rug

Lumpy Rug Day
kiss a brunette

Kiss A Brunette Day
girl friend

Girl Friend Day
pick me

Pick Me Day
artists

Artists Day
stud

Stud Day
slime

Slime Day
polyamory

Polyamory Day