Am not 100% sure. I can only theorize.
The NDE Core helps with the physical shifting of the D. And since the subconcious programming starts in the mind, that could in turn translate to feeling that you have a big dick.
And the physical can impact the psychological. Wherein someone who has a big dick (or big muscles, or a big house, or a big car or a big bank balance), feels more confident. This one can gain by having the NDE Core in a custom or running BDLM.
A similar principle applies when oneās sexual energy is ābigā or abundant. When one has cultivated it and doesnāt waste it. In which case that sexual/spiritual energy also translates into the psychological and one is more confident as a result of the energy one has. This one can gain by running Khan Black.
Itās all connected.
Also, I wouldnāt term this as an insecurity but I do agree that it does mean one is more confident when one isnāt worried about his size and is cool and confident regardless of it.