Combine cream cheese, feta cheese, milk, and freshly ground pepper in a small mixing bowl. Beat with an electric mixer on medium speed until mixture is well combined and of desired spreading consistency. Cover and chill until ready to serve, up to 3 days.
To serve, spoon cheese mixture into a serving container and place on serving platter with vegetable dippers and crackers or on dinner rolls. Makes 15 to 20 servings.