Crush the digestive biscuits in a food processor or in a plastic bag with a rolling pin, and add to a mixing bowl.
Chop each marshmallow into 4 pieces and add to the bowl with the cherry halves.
Add ½ cup of sweetened condensed milk. Mix until the ingredients are well combined and you have a sticky mixture.
Add more condensed milk if the mixture is too dry and not holding together.
Sprinkle the coconut over a large piece of plastic wrap or foil. Roll the biscuit mixture into along roll about 2 inches thick. Roll in the coconut to coat completely.
Wrap the plastic wrap or foil around the roll and refrigerate for at least 4 hours.