Flow Control

Flow Control, along with Mana Gathering, are the two ways to manipulate the world on Enies. However, unlike Mana, the ability to control Flows is innate and cannot be learned. Only Imir and their descendants are able to bend Flows to their will, any offspring of a mixed couple sees their ability to do so reduced.
Although Flows have always been present, no species were able to wield it before the aftermath of the Astral Extinction. And even then, Imir exiled to the furthest North Western lands when they learned of the Truth of the World, keeping the secrets of Flow Control to themselves.
As it goes, Flows are easier to control than Mana due to the very nature of what Flows are. Unlike Mana, which is a sort of energy stored within the body, Flows are continuous never-ending streams of raw natural energy coming from the planet itself. To order one, all that's needed is to understand its nature and politely ask them to perform what was intended. Because of Flows' raw nature, providing a mental image of the desired outcome aids them greatly to perform beyond natural phenomena.
In some cases, an abudance of Flows in one place can have an effect on the surroundings. If the soul of an Imir mixes with the abundance of Flows, it creates a Puqèxa, a tangible Flow sprite which can bless the land as well as curse it, and only another Imir may calm its fury from an equal ground. Otherwise, Flows can cause natural disasters on repeat until the issue is solved.
Ultimately, Flow Control answers to the simple rules of politeness and understanding to improve one's chances to have the Flows accepting the request.
Since the requests do not require any energy from the one asking, it can technically be used constantly. However, doing so might upset Flows, who would greatly enjoy having a break after hardenous work.