My little brother recently got into the Pokemon TCG, and after explaining to him that energy used in an attack remains with the Pokemon, he attempted to repeat the move using the energy already attached. There's no indication that this is legal or illegal, so I'm kind of lost. To use the same move do you simply add more energy?
As long as there is sufficient energy behind the Pokemon to use the move, that move can be used repeatedly in subsequent turns using the same energy if your little brother wants, but the move can only be used once per turn.
It's only if the energy behind the Pokemon gets discarded in some way (perhaps by the effect of an attack or by a crushing hammer) can the active Pokemon no longer use that move if they no longer have the required energy behind it.
Hope I helped! Source: Experience