first, sorry about what you went through as a kid. you definitely had some tough stuff to deal with.
second - i don't claim to have the definitive answer for you. from what you said, i understand that your dreams used to be a reflection of what really happened - including the important fact that it was unwanted, but recently they have become distorted with the implication that since you seemed willing, eager and active in the new dreams - you must have also felt that way back then when it happened - or worse - that you want it that way now.
let me offer another interpretation - you also said that at the time it happened you did find pleasure in the orgasm. i think what your dream is showing is that confusion of something "unwanted" conflicting with the fact that it was also something that gave "pleasure." that is a difficult place to be - feeling like the rope in a tug of war. i have been there - and still visit from time to time.
third - you didn't say if you have seen a therapist or have the opportunity to do that. or how long you have been dealing with the CSA issues. to me it sounds like what i was going through when if first opened the lid of pandora's box and started facing my issues. EVERYTHING became sexualized. i had repressed it all for so long that it came back to bite me with a vengeance. it was confusing and disturbing. but it didn't necessarily mean anything more than that i was feeling lots of stuff very intensely and was mixed up from the assault - like you say - consumed. maybe that is what is going on for you?
fourth - i've often wished i could turn back the clock to before i started this long and bumpy road of recovery. but when i think back honestly on what it was like then - it wasn't really better - just familiar. i believe you will find your way out the other side and it will be better.
They have greatly oppressed me from my youth, but they have not gained the victory over me.
Plowmen have plowed my back and made their furrows long.
But the Lord is righteous; he has cut me free from the cords of the wicked.