on command
When it is ordered or desired; through conscious volition.
The actor could cry on command.
Inexperienced mages usually cannot cast spells on command.
I find it very hard to sit down and create an idea or especially a new character on command. Usually my characters evolve by accident out of some story context. John Kricfalusi
It's such an advantage to be able to hit short irons low on command. When it's windy, you'll hit more greens. But low shots are a great strategy in calm conditions, too: The less time the ball hangs in the air, the less time it has to stray off line from the flagstick. Keegan Bradley
There are several books that I have-the Physics of Star Trek, Star Trek and Business, there are manuals on command style and countless scholarly papers that have been written about the significance of Next Generation. Patrick Stewart