pretty simple...for example, the Mr. Farmy Robots in Deon's Wasteland have:
[USE_MATERIAL_TEMPLATE:PASTE:CREATURE_EXTRACT_TEMPLATE]
[STATE_NAME_ADJ:ALL_SOLID:frozen sailent paste]
[STATE_NAME_ADJ:LIQUID: sailent paste]
[STATE_NAME_ADJ:GAS:boiling sailent paste]
[STATE_COLOR:ALL:GREEN]
[DISPLAY_COLOR:6:0:0]
[PREFIX:NONE]
[EDIBLE_VERMIN]
[REACTION_CLASS:SAILENT_PASTE]
[MATERIAL_REACTION_PRODUCT:DRINK_MAT:LOCAL_CREATURE_MAT:SAILENT]
[USE_MATERIAL_TEMPLATE:SAILENT:CREATURE_ALCOHOL_TEMPLATE]
[STATE_NAME_ADJ:ALL_SOLID:frozen sailent green]
[STATE_NAME_ADJ:LIQUID:sailent green]
[STATE_NAME_ADJ:GAS:boiling sailent green]
[PREFIX:NONE]
[REACTION_CLASS:SAILENT]
[MILKABLE:LOCAL_CREATURE_MAT:PASTE:20000]
with the workshop reaction:
[REACTION:MAKE_SAILENT_GREEN]
[NAME:distill sailent green]
[BUILDING:STILL:CUSTOM_S]
[REAGENT:paste:150:LIQUID_MISC:NONE:CREATURE_MAT:NONE:NONE]
[UNROTTEN]
[REACTION_CLASS:SAILENT_PASTE]
[REAGENT:container:1:NONE:NONE:NONE:NONE]
[CONTAINS:paste]
[PRESERVE_REAGENT]
[DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[REAGENT:barrel/pot:1:NONE:NONE:NONE:NONE]
[EMPTY]
[FOOD_STORAGE_CONTAINER]
[PRESERVE_REAGENT]
[DOES_NOT_DETERMINE_PRODUCT_AMOUNT]
[PRODUCT:100:5:DRINK:NONE:GET_MATERIAL_FROM_REAGENT:paste:DRINK_MAT]
[PRODUCT_TO_CONTAINER:barrel/pot]
[PRODUCT_DIMENSION:150]
[SKILL:BREWING]
and an old one I did (and later Crioca cleaned up) into adding Kefir to cow/sheep/goat milk is simply adding:
[REACTION_CLASS:MEAD]
[USE_MATERIAL_TEMPLATE:MEAD:CREATURE_ALCOHOL_TEMPLATE]
[STATE_NAME_ADJ:ALL_SOLID:frozen kefir]
[STATE_NAME_ADJ:LIQUID:kefir]
[STATE_NAME_ADJ:GAS:boiling kefir]
[PREFIX:NONE]
right underneath a creature's milk material
and then changing the first reagent in the mead reaction to:
[REAGENT:honey:150:LIQUID_MISC:NONE:CREATURE_MAT:NONE:NONE][REACTION_CLASS:MEAD]
(mind...with this way, we had to add [REACTION_CLASS:MEAD] to the bees Honey material to actually be able to still make mead)
Your best is Deon's method...just change the names and copy into your new creature and reaction raws.
EDIT: Put that $#*% in Spoilers...