Demiboyflux is a combination of demiboy and boyflux. It's a term for when one feels some connection to masculinity, but they never feel completely masculine and their gender fluctuates. At one's most masculine, they feel like a demiboy. At one's least masculine they feel may experience other genders.
The name may also be be interpreted as someone who is partially, but not fully boyflux.
The feminine counterpart is demigirlflux and the neutral counterpart is demigenderflux.