Place the mustard in a mixing bowl or the bowl of an electric mixer. Add the mayo and beat for 1 minute Add the Worcestershire sauce, steak sauce, cream, milk and a pinch of salt. Beat until the mixture is well-blended and creamy. If you'd like a little more mustard flavor, whisk in about 1/2 tsp more dry mustard until well-blended. Chill the sauce, covered, until ready to serve.