Boundaries, borders, frontiers, limites...
These define the extent to your personal sovereignty, and your autonomy, within which only you are king.
Nice.
It's also a fucking terrible analogy which implies that you wish to keep a part of yourself eternally separate from others. Yes, the metaphor serves as a self-preservation mechanism, though it is a jealous and extreme one.
It is the overreaction of the unsure self and an insecure expression of personal sovereignty.
This is a metaphor founded on fear and the feeling that others are inherently dangerous. It is the Trumpism of self-ideation.
With regard to myself, I might prefer to think of the 'self' in terms of a state governed by laws. Others can come into my state, but they must obey the laws and the customs. They can rest completely within my core, and find succour within the bosom of my soul, if they wish. You can be a 'good citizen' of my soul, in those terms, and live out your days knowing me inside and out - there is no part of me where you cannot wander, because you are true to the compact of my laws and you have earned the right. Break the laws, however, and you will be ejected from the inner circles of my 'state'; continue breaking them and you might be completely banished.
Whether 'boundaries', 'laws' or something else, our choice of metaphorical language imbues our sense of personal sovereignty and autonomy with an essential character derived from its symbolic caché. This is unavoidable, and we would do well to be or to become highly sensitive to such things.
Great thread idea.