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

Other days

fiancee

Fiancee Day
kiss a brunette

Kiss A Brunette Day
self appreciation

Self Appreciation Day
bounce

Bounce Day
bubble bath

Bubble Bath Day
gum

Gum Day
nail polish

Nail Polish Day
slime

Slime Day
comfy

Comfy Day
first love

First Love Day