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

Other days

martini

Martini Day
boy friend

Boy Friend Day
hiv awareness

Hiv Awareness Day
slime

Slime Day
tell a fairytale

Tell A Fairytale Day
nail polish

Nail Polish Day
ride the wind

Ride The Wind Day
tulip

Tulip Day
boba

Boba Day
gum

Gum Day