Does the exit of a viscous fluid upon waking from an erotic dream, without feeling lust or ejaculation, necessitate Ghusl?

This discharge that exits, it should be examined whether it is manī (seminal fluid), madhī (pre-seminal fluid), or wadī (post-urination discharge), and its ruling will be according to that. If you are unable to determine its nature, then you may choose and assign it the ruling of one of the three, and act according to what follows from that.