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

Other days

boba

Boba Day
carpenters

Carpenters Day
ruby

Ruby Day
buddy

Buddy Day
cuddle up

Cuddle Up Day
kiss a ginger

Kiss A Ginger Day
comfy

Comfy Day
polyamory

Polyamory Day
lisp

Lisp Day
coffee

Coffee Day