Here is what you need: liquid porcelain clay (I poored it in a washing liquid container so that is easier to use), a mould, a glas jar or two, a filler with a sieve, oxide or stains, a sponge and two flat wooden sticks.
First we will color a bit of liquid porcelain clay. Put a bit into a jar.
Add oxide to it.
Stir it a bit an put it through a filler with a sieve so there is no lumps in the clay left and that the oxide is solved well.
Poor it back into the jar so that it has been sieved twice.
When it's ready, poor a bit of the colored porcelain slib into the mould and twist it around a bit.
Then fill the mould with white porcelain clay.
Let is set for 10 minutes.
Poor the liquid clay back into the container.
Put the mould upside down on the flat wooden sticks.
Cut with a knife the edge of the cup away and turn the mould around on the wooden sticks.
After a while, you see that the edges of the clay will come loose from the mould.
Turn it around and the cup will fall out of the mould. Let it stay there for a while until it is a bit dry because it's still soft. 
Then take a wet sponge and rub it softly around the edges so to get the sharp edges away.
Now let it dry slowly & then fire it.
