Use glycerine to soften royal icing or as a sugar substitute.
Sugarflair Glycerine - 45g
An odourless liquid to use when making royal icing, to ensure it has a softer consistency for coating. A recommended quantity is 1 tspn/5ml - 1 lb/450g icing sugar. (Do not use with icing made for piping, runouts, extension work etc where stronger icing is required).