Hi Narayan,
My understanding of the big draw is that when you are getting close to orgasm (or just anytime you want to release the buildup of energy/sensations) you contract the PC muscle (or perineum; not sure if there is a difference) while inhaling, then exhale and release the contraction sending the energy into the tailbone and up through the spine to the head.
When I do that I get really strong (and pleasurable) sensation in my tailbone, and I can follow the energy through my spine; Although I still need to open up the channels along my spine more because the “signal” fades as it reaches the middle of my spine.
And you don’t have to do it to avoid orgasm, you do it to direct the orgasmic energy. That way you get to experience the orgasm and not ejaculate. It’s like a voluntary orgasm. So you don’t wait until you fall over the edge, you jump while you’re in full control (hope that analogy makes sense).
I should give multi-orgasmic man a full read. I stopped half-way through when I realized it is a simplification of the broader Taoist meditation practices for the sake of readers only interested in sexual mastery. Because of this, I think it lacks a certain depth. I’ve spent more time reading some of Master Chia’s other books for a deeper understanding of Taoist meditation as a whole.