What is the meaning of this sentence?

I saw this sentence when I was reading about “lucid dreams”. Could you please tell me the meaning?

You can try shape-shifting when you are lucid dreaming. It is hard to do it on command, but you can also make an ‘excuse’ to transform by making a transformation machine or a magic assistant that can change you into an animal.

I need to confirm myself that my interpretation of the above sentence is correct. So please help me (especially the one in italics).

It is hard to do it on command = it is hard to will yourself to do it at the time/into the shape that you wish it to happen. (It is easier if you just allow it to happen naturally without trying to make it happen at a certain time or into a certain shape).

make an ‘excuse’ to transform - I’m not sure ‘excuse’ would be the correct word and can understand why it is in inverted commas!
I would use ‘make it easier to transform by…’