Oops, it doesn't look like 'flag week and flag day' is a national day..

Other days

self care

Self Care Day
aloxolt

Aloxolt Day
boba

Boba Day
azonto is acceptable

Azonto Is Acceptable Day
tulip

Tulip Day
bounce

Bounce Day
martini

Martini Day
stud

Stud Day
cuddle up

Cuddle Up Day
nae nae

Nae Nae Day