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

Other days

polyamory

Polyamory Day
china

China Day
pampering

Pampering Day
ride the wind

Ride The Wind Day
coffee

Coffee Day
artists

Artists Day
one

One Day
boy friend

Boy Friend Day
bow tie

Bow Tie Day
boba

Boba Day