Be sure not to over water that baby. Also, I am only saying this because I have a tendency to over water some of these cactus, so I water from the bottom because they drink through their little bulbs of roots and those roots hold water, so you may think they are dry by touching (which I also do) the top but I do not trust that method all the time since the bottom can get root rot without the top showing it until they start to fall apart. This works for me. No one ever told me there is only one way to do things and I like to pass on information but with the comment that it may not be the way the book says, but it works for me.
