Must I "stand" in order to "stand still"? [closed]

When I tell someone:

Stand still!

do they need to be standing at that moment? When I tell someone:

Sit still!

do they need to be sitting at that moment?

If yes, is there a more general statement (edit: preferably including the word "still") that can include both?

Edit: I probably should have given a better context to my query. I am thinking of a situation when you tell someone to stand/ sit still, so you can do something:

Stand/sit still or I will pierce you instead of your shirt with this pin!

Does the reader guess from that the position the person spoken to is in?

Solution 1:

Yes. If you tell someone to stand/sit still they do need to be standing/sitting at that moment.

"Keep still" and "Don't move!" are commonly-used commands that include any position they may be in.