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

Other days

boy friend

Boy Friend Day
ruby

Ruby Day
bow tie

Bow Tie Day
youth

Youth Day
lisp

Lisp Day
latina equal pay

Latina Equal Pay Day
blanket fort

Blanket Fort Day
nae nae

Nae Nae Day
stud

Stud Day
believe

Believe Day