Succubus manifesting as a family member, truth or myth?

Now hear me out before you lash,

I heard a couple of ’ conceptions ', for lack of better words, that state that Jinns/Succubus can come to you to have sex with you in your dreams and often would manifest as a family member ( close relative, brother, mother, sister… ) now to each his thing, but the person who told me suffering from this is nowhere near being intrested in incest.

I have also heard/read that to differentiate a succubus act from just a ’ wet ’ dream is if your partner in your dream changes form/shape/person during the act itself… This part I have experienced myself but have no idea if it was just a weird wet dream or indeed a presence

Any thoughts on the subject?

A succubus or Incubus will take on the form that is more appealing to the one they’re doing it to, or keep their true form which is pretty human looking with minor differences. If they are doing such to a person who doesn’t like it then that’s possibly the succubus not liking him or a parasite he/she believes is a succubus.

As for the way to differentiate, hmm, not really since changing form during the act can still be dreaming.