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

Other days

Slime Day

Stud Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Boyfriend Day

Boy Friend Day

Nae Nae Day

Pick Me Day

Promposal Day

Polyamory Day

Chocolate Milkshake Day