Usage of Ajapa - Japa is maybe the way to forward with spinal breathing if not initiated by a guru. Since it is synchronized with the breath it is supposedly the way to be meditating the whole day building up for final meditation round.
It goes like this Breathe in , Kundalini rising up the spine , mental sounding of word so
It goes like this Breathe out, Kundalini going down the spine , mental sounding of word ham.
goes like this so-ham , so-ham, so-ham and so on.
The word "so - ham" is the yogic way of saying "I am" .This is said by the body all over the day while respiring. The root word is "Aum" from which "so-ham" arises , called in sanskrit "Aham" in english "I-am" or conscousness of self erupts.
Let me know if this works for you.