that's how i do it when i am lucky enough to find fresh or liquid in the dairy section. or am using a combo of heavy cream and aloe juice or any veggie puree.
i just make sure that the oils are cool ( just barely warm to the touch when you wrap your hands around the outside of the soaping pot ) or room temp.
depending on the fragrance, cause some heat like a rocket on their own i may or may not put the milk cubes in a cold water bath too. so everything is almost cold when i mix.
dump the lye on the cubes and stir the pewillies out of it ( be careful of splashing ), till all the cubes are melted and the lye is dissolved.
i will run my sb in this mixture on low ( be real careful if you do this and start out with the sb on the both of your container and do not raise it up if the blender is going ). this helps break up the milk fat that has started trying to bind with the lye by itself while the rest of the milk was melting. i then pour this thru a very fine ss strainer just in case there is some undissolved lye, although with adequite stirring this has never been a problem.
depending on how long this all took, the mixture is off white to lemon colored and gives me a light cream colored soap base if left uncolored and the fragrance doesn't discolor.