Incest in dreams can be a difficult symbol to define. The dreaming mind does not usually discern between what’s moral or immoral.
The act of sex itself represents the merging of two personality traits or qualities. So sex with parents, siblings, or other family members is most often just a symbol for different personality traits or qualities merging. The family members are usually like any other dream symbols…personality traits based on your opinions, feelings, or memories of them.
If you not aware of the incest as it occurs in the dream, and feel like there nothing wrong with it , then the incest as a symbol is probably irrelevant. The sex is the most significant symbol. The family member is just an emotionally awkward or uncomfortable symbol.
Sex with parents may reflect a positive experience you’ve had making a choice.
To be aware of incest in a dream, to overhear talk of it, or feel that it is wrong represents taboo, or a lack of acceptance for something.
Alternatively, you may have personal issues with a family member you need to address.
If you have experienced incest in real life then you may be having problems dealing with that or are reexamining the past.
Example: A man dreamed of his father slowly pushing his penis into his bum. In waking life he was conscious of himself about to make a bad decision that would have consequences. His father trying to have anal sex with him reflected his conscience or ability to make a decision that was about to screw him over.