I can't believe I am writing this on a furry forum.
Ok so guy is probably serious and talking about astral traveling or lucid dreaming, which is leaving your physical body with consciousness and moving in a space which we would call "dreaming space" (when you go there It feels as real as dream, but some people who projected into astral plane say I is more vivid and real then this plane. Probably because you don't use a brain to decode that reality, rather you see through naked awareness).
You don't need to join or fight anybody to become your fursona in astral dimension, but why would you even want to have a body- they are gross, wet and can die and rot. You automatically manifest your thoughts when you leave consensus reality (like physical dimension). Just don't get reincarnated on earth because that can happen too If you go to the light, basically you can't trust spirit guides or your deceased loved ones If you don't want to go back to earth. Just have intention to leave this reality.
Sex with anything you want? - pretty gross way to entice somebody. I doubt op has good intentions. This seams like some cultish stuff.
You can Ask me about anything inside of this post and I will provide sources.