"Any Mummers 'Loud In" is a phrase from the famous Newfoundland Christmas song called "The Mummers Song" by Simani.
Mummering used to be a tradition every Christmas Season. People young and old would dress up with their bras and underwear on the outside, mittens on their feet, socks on their hands, rubber boots on backwards, pillow cases covering their faces, and anything they could find to disguise their identity. They would then get together and go visit their neighbours, dancing, laughing, and having a "scattered swallie." Nobody really knew who was visiting them, or who the mummers would be, but they would come, have a good time, and then they would be off to the next neighbour.