Wiktionary
n. (context psychoanalysis English) In Freudian theory, the first time a child witnesses (and understands) its parents copulate.
Wikipedia
In psychoanalysis, the primal scene is the initial witnessing by a child of a sex act, usually between the parents, that traumatizes the psychosexual development of that child. The scene witnessed may also occur between animals, and be displaced onto humans.
The expression "primal scene" refers to the sight of sexual relations between the parents, as observed, constructed, or fantasized by the child and interpreted by the child as a scene of violence. The scene is not understood by the child, remaining enigmatic but at the same time provoking sexual excitement.
Usage examples of "primal scene".
I looked out at the primal scene: two Mesozoic monsters, here through the grace of modern genetic science, and a thin brown woman, likewise.
This eerie soap opera repetition is the postmodern equivalent of Freud's Primal Scene, or of Nietzsche's Eternal Return.
In classical psychoanalysis the big thing was the primal scene, when you saw or heard your parents making love.
Although the writer had badly botched this conclusion, I assume that the Primal Scene was enacted by all these characters in turn, in every conceivable combination, under the obscene prompting of Mother Hubbard, who had assumed a Hecate-identity with the coming of darkness.