Hopefully, those are two different questions
All wood moves, even if it is at it's equilibrium moisture content.
Red cedar would either have to be turned bone dry or sopping wet. If wet, you will need to rough turn it thick, then you need to slowly dry it. One method would be to put it in a paper bag and change the bag every couple of days. You know it's dry when it quits loosing weight.
If bone dry, then I would turn as any other wood, but be really careful during sanding so that you keep the heat on the wood to a minimum. At that point, it may still move, because you have released stress in the wood.
Af far as coffee, I would look at some sort of epoxy coating, but I don't know how foodsafe that would be. Another idea might be to get a ceramic insert for a wood mug.