When will I be able to DO the posture?

A question I love to address occurs commonly with regards to Fixed Firm Posture.
I hear something like: “When am I going to be able to do the posture?”
I smile in response: “What are you talking about? You are already doing it. I have seen you do it several times a week for the past 5 months.”
“But I am terrible at it. When am I going to be good at it?”
The question I must ask in return:
What do you mean by “doing” a posture? Or being good at it? And what is the purpose of the posture?