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

Other days

gum

Gum Day
blanket fort

Blanket Fort Day
my little pony

My Little Pony Day
cursing

Cursing Day
martini

Martini Day
camera

Camera Day
stud

Stud Day
kiss a ginger

Kiss A Ginger Day
first love

First Love Day
law

Law Day