There is an interesting drift of terminology in the usage of the various masters of Kundalini Yoga. The expression "breath of fire" seems to denote the tantric yoga kriya Candali (gTum-Mo in Tibetan) which is fundamental to the Six Yogas of Padmasambhava.
But Teresa's account is of a technique closer to what Sw. Gitananda Giri taught as bastrika, a preparatory kriya. Pieter then describes a set of Kundalini Yoga kriyas known to me, again, by a different name - rather similar to the Bengali Laya Yoga kriyas taught by Sw. Gitananda and imparted to him by Sw. Kanakananda Brighu.
Different yet again is Sw. Rama's description of Laya Yoga. He outlines a kind of Nada Anusadhana more akin to Shabda procedures with their Anahata sounds than to Laya Yoga in either its vaidika or tantrika form, which both require vivid visualization and highly developed mastery of pranayama.
All of these techniques are valid and valuable. It is the variety of names they have acquired that I find so remarkable.