Temporality is fundamental for understanding all experiences related to substance use, and, a fortiori, misuse (Messas et al. 2019b). From a temporal perspective, the main purpose of a voluntary act of substance use is to remove oneself from the habitual conditions of biographical temporality. Consciousness modification therefore reflects a search for new proportions of anthropological proportions, a new expression of existence (Messas 2014b) in which the dialectics between present, retention and protention might be modified by the historical self. For example, say somebody has a few drinks with friends after a demanding day's work. Their purpose in doing this is to temporarily release themselves from the worries of their job. By engaging in an experience that is intense and isolated in the present, they temporarily cut off any connection with the recent past, which, from an existential perspective, may be salutary. However, if retention is reduced to such an extent that all sense of social protocol is lost (e.g. a person who drives under the influence and thereby breaks the law and puts third parties at risk), this self-management can be defined as harmful.The possibility of instantly managing the dimensions of temporality interacts ambiguously with existence itself, sometimes enabling its expansion, sometimes its deconstruction. The capacity to move one's own temporal foundation grants the historical self unusual Dionysian powers over the plasticity of temporality -the ways the dimensions of retention, present and protention are articulated. And, as we will see below, this power extends through temporality to affect the other conditions of possibility of existence. It is the existential meaning of this self-mastery of the proportions of temporality that makes it harmful, productive or ambiguous.