For me the spinal breath of Kriya Yoga was always really powerful, but also quite overwhelming. If it works for you, fine. But if you practice this technique and experience some energetic problems or even regular health problems for that matter, you can try this:

This is a Taoist practice called the Microcosmic Orbit. Very similar to the spinal breath (Kriya Pranayanam). The difference is, you start at the navel go down to the perineum, up the spine and down to the navel again (tongue at the roof of the mouth to close the circuit). You balance the front and the back of the body, keep the energy circulating and purifying/healing. I find this a much more balanced and healthy feeling practice than the Kriya one.
Just letting you, Kriya Yogis, know that there is something like this out there