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

Other days

boy friend

Boy Friend Day
cuddle up

Cuddle Up Day
nail polish

Nail Polish Day
my little pony

My Little Pony Day
ponytail

Ponytail Day
offer

Offer Day
boba

Boba Day
lost sock memorial

Lost Sock Memorial Day
aloxolt

Aloxolt Day
gum

Gum Day