Well, to make a cream stout, you'd add lactose (milk sugar) to the boil. Lactose isn't fermentable by yeast and will thus leave more body - a 'creamy' mouthfeel.
If you had the proper dispensing system, you could 'cream' your stout. Nitro taps are used to create smaller bubbles/less CO2 and thus create a 'creamy' head.
so, exactly what are you referring to?