According to Osho, entry in mediums occurs through receptive 'feminine' openness: the medium consciously empties inner space and, like a tuned radio, invites a nearby disembodied soul to enter and communicate. This differs from actively entering another’s body. Fear can create an accidental vacuum that attracts ghosts and trouble; deliberate, aware invitation is safer, with known routes for entry and exit, whereas invoking embodied souls is hazardous.
A medium is like a radio that makes room inside and politely lets a wandering spirit use their body to speak; fear can open that room by accident and cause problems.