Demigenderflux is a combination of demigender, and genderflux. It's a term for when ones gender fluctuates between demigenders, but they never feel a particularly strong connection to either binary gender. For example, at their most feminine, they feel like a demigirl, and at their most masculine, they feel like a demiboy. They can also at times feel like other genders.
The feminine counterpart of demigenderflux is demigirlflux and the masculine counterpart is demiboyflux.