A tip, in case anyone is trying to implement this and finding it hard: Try adding a bit of cream to a glass of soda, preferably soda from a can or freshly opened bottle for the carbonation. The result is a variant on an egg cream soda, and may be useful in terms of getting used to the flavor and texture of the cream. (I've only tried this with fruit sodas, mostly cherry flavored; I expect it's similarly tasty using root beer or cola if one likes those.)