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

Other days

martini

Martini Day
frozen yogurt

Frozen Yogurt Day
pick me

Pick Me Day
slime

Slime Day
cursing

Cursing Day
nae nae

Nae Nae Day
book

Book Day
unicorn

Unicorn Day
bow tie

Bow Tie Day
youth

Youth Day