The genealogy of the concept of après-coup is isomorphic with the process to which it refers, one that is inherent to thought and desire. This genealogy followed the detour of Nachträglichkeit before flourishing in French psychoanalysis with the term après-coup. The operation of après-coup is a process that unfolds in two stages and realizes a regressive psychic work in the interval period of latency. This configuration is explained by the fact that there is a solution of continuity between the extinctive tendencies of the drives and the imperative of registration that both opposes them and makes use of them. The operation of après-coup is the method that the psyche has at its disposal for processing these traumatic tendencies linked to the numerous daytime traumas. It allows for the libidinal regeneration of mental life and object-cathexes. Irrespective of the place this concept has in the metapsychological corpuses of the psychoanalytic schools, the session work seeks to make this process and its functions operative.