Co-regulation is the process through which nervous systems support and influence one another through relationship, presence, tone, and shared regulation. It is not simply a technique for helping someone “calm down,” nor is it a gentler route to compliance. Through the Interbrain, cues of safety can help reduce stress and support a shift toward a more regulated state. But the process is reciprocal: stress can also beget stress, creating co-escalation. The Self-Reg shift is to recognize that regulation is relational and that our own state matters. Co-regulation sits at the heart of Self-Reg because relationships can change stress, energy, and the capacity for regulation itself.