Muse, you got me doing things I will never do
Fill me up with creative juiceCreative Juice (Afro Nostalgia)
Creative Juices, colloquially known as 'Juice', is the main form of energy that powers the Dreamscape. It represents Jo's raw creative activity and effort. It appears as a viscous glowing yellow-pinkish glowing liquid, and when left to pool it forms mildly dangerous vibrating puddles with occasional sparks. Muses themselves are made of focused Juice, and are occasionally spontaneously generated where large quantities of it gather - though this can have unexpected consequences.
Most things in Dream, from the powers and basic biology of Muses to Vignettes and the mundane juicetronic devices are powered by Juice - these latter contraptions function in a similar way to real-world electrical devices. A large reservoir of it is stored in the Juice Battery above NFWS headquarters for this purpose, at the centre of the network of pipes that distributes it throughout Spindle. A Muse's internal Juice can also be used to power things when necessary, but attempts to get Juice into a Muse from outside have only resulted in injuries.
Whenever a Muse contributes to Jo's creative output, this generates Juice - some of which replenishes their internal stores. The excess will harmlessly evaporate into the environment, unless it is captured first. As this externally generated juice can't be used directly by the generating Muse, Muses are generally happy to participate in NFWS's collections that refill the Juice Battery, and perhaps more to the point, if they refused they would find their house cut off from the Juice grid and have to go through the hassle of powering it on their own.
Most uses of Muses' powers tend to contribute towards Jo's creativity, and thus end up being net positive in Juice used and gained, but if a Muse's internal store of Juice gets too low, they will eventually Fade entirely. The external type of juice that NFWS collects does not protect against Fading any more than your body heat would protect you from starvation.