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

Other days

cursing

Cursing Day
ruby

Ruby Day
unicorn

Unicorn Day
stress awareness

Stress Awareness Day
first love

First Love Day
nae nae

Nae Nae Day
hoodie

Hoodie Day
mean girls

Mean Girls Day
carpenters

Carpenters Day
bow tie

Bow Tie Day