Oops, it doesn't look like 'stretchy pants or no damn pants day' is a national day..

Other days

hiv awareness

Hiv Awareness Day
brow

Brow Day
donate your hair

Donate Your Hair Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
slime

Slime Day
offer

Offer Day
my little pony

My Little Pony Day
stud

Stud Day
blanket fort

Blanket Fort Day
ponytail

Ponytail Day