In this article, a psychoanalytic analysis of the Hain ceremony of the Selk'nam people is undertaken with the aim of reflecting on the construction of masculinity and the threats underlying it. This ceremony, which is central to the transition from childhood to adulthood in the culture, is based on a myth chronicling the existence of a prior matriarchy. The fear of the return of this regime gives rise to a ceremony symbolising a counter-response, sustained by a pact of silence among men. The underlying threat is rooted in the fear of female domination and submission to women. It is suggested that this myth contains a specific truth connected to contact with vulnerability. It is proposed that the combination of an intense mother–son relationship, coupled with distance from the father during the early stages of development, is connected to the threat of regression to a mother–child bonding state as a form of protection from the anxieties associated with facing the world. At the same time, this generates the need to establish defensive barriers towards women.