Hm... When I was feeling I really needed affection from my family, I had this dream in which my sister and I had sex. I've never seen porn and never been sexually active. And I'm a girl and I'm straight as far as I can figure out, but I was having sex with my sister. To whom I feel absolutely no attraction whatsoever.

In the dream my sister was kind and playful and seemed to really love me, which I felt was missing in my real life. Maybe the sensations you felt were more important than the story? I don't know — did you feel proud, unhappy, forced, chilled out? That would give a better indication as to the meaning of your dream because it says what your attitude towards the ideas in the dream was.