Topological defects in general and Chern-Simons in particular

I’m trying to gain intuition on some physical concepts that I cannot yet fully understand, and I think many of you can help me.

Is it correct to think of of a topological defect as the addition ad hoc of some term to an action that couples appropiately with the physical fields of the theory? For example, if I have a gauge connection, this can couple to a curve, and I can integrate the gauge connection along the curve.

Is it correct to say that adding this term to the (hypothetical) action "creates" (clearly in a a topological defect in the theory? Can there be dynamically created defects that werent ad hoc inserted? In the first case, I’m adding a defect classically, so this is present before any quantization, But I also see that one considers the expectation value of the term, I dont understand what’s the meaning of this, one considers how quantum fluctuations alter the classical value?
What happens if I do the same procedure whitout adding the defect classically?

Maybe my questions are a bit vague, I apologize but I’m really struggling to understand this things, that are not so mathematically precise I think are more of an intuitional nature. I thank you in advance.