Well my friend, there are a few things I do to keep my moss like that.
First thing is to make sure you tie your moss onto the wood evenly and imagine it grown out. Envision it in its future state, more towards its final photograph.
Second, keep your moss tight. Once the moss grows out and you can see it attached cut it down low. Keep the moss short until it is full. Thin moss is spindly moss, we don't like spindly moss!
Thirdly keep it clean! Turkey baste or pat your moss with tweezers. Do not let algae build up in it and allow the base to die. The base is what keeps it attached correctly.
Lastly, keep your moss in shape and train it. I cut my moss low to a bit longer from top to bottom. The higher moss grows faster and the lower moss grows slower. This way the light from the top doesn't block out the plant at the bottom and keeps it nice and even.
And that would be how I get my moss to grow in the fashion you mentioned, I allow it to. Most people unknowingly don't allow their plants to grow out in a natural way because of their lack of maintenance or no for thought.
Best of luck with your moss and let me know if you need any help.
Oh and use ADA curved scissors.