The term "Mug Up" was used in coastal communities by the
mid-1800s to describe any snack or coffee
break throughout the day or evening.
“Mug ups" were an important part of life for fishermen. They would gather and have a hearty meal and warm up whenever they could take a
break. Today, this nautical expression still describes a gathering of
people for a drink and meal
Today, Mug-up is used by Scouts Canada to describe an evening snack (after dinner, but before Campfire). It is usually soup or hot chocolate and something to munch on (grilled cheese, etc).