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

Other days

kiss a ginger

Kiss A Ginger Day
law

Law Day
hoodie

Hoodie Day
reading

Reading Day
nae nae

Nae Nae Day
ask out your crush

Ask Out Your Crush Day
kale

Kale Day
get funky

Get Funky Day
fiancee

Fiancee Day
bow tie

Bow Tie Day