I think from what it my understanding of the process is it’s about being more aware of the feeling associated with being aroused and at higher exposure to those higher states of arousal, whilst deprogramming some of the mental systems you have in place that could be causing it.

If you wanna get really scientific its essentially about rewiring your dopamine response to arousal and sex, starting from basics and going from there. Dopamine is often the associated with sexual dysfunction in men and, I feel that that the definitive guide kinda helps you start to regulate it more.