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

Other days

stud

Stud Day
lisp

Lisp Day
brow

Brow Day
eat what you want

Eat What You Want Day
ormille

Ormille Day
nae nae

Nae Nae Day
first love

First Love Day
special education

Special Education Day
kiss a ginger

Kiss A Ginger Day
gum

Gum Day