[QUOTE=Surya Deva;69870]My Tantra guru told me that to switch from IDA to PINGALA or PINGALA to IDA you need to lie down on the ground, head supported with your elbow on the opposite side to the one you want to switch to for about 10 min. Then the switch takes place, and you will be able to tell by which nostril you are breathing through predominantly.[/QUOTE]
Your tantric guru, I believe from my own research/explorations/experience etc, is correct here; This appears to be the best method i know of.You lie on the ground on your side opposite the nostril you wish to open or flow, say for e.g it is blocked.
Pingala- Right Nostril
Ida-Left Nostril.
Focusing on one is dangerous whether ignorantly/unwittingly or not and the texts warn about it.The aim is to find balance so the central spiritual channel or sushumna nadi can awaken safely.If you don’t have sufficient balance you can risk imbalance by waking up sushumna albeit temporarily too soon.
I could be wrong but the phenomenon the OP describes that of ’ perhaps you don’t need to do anything to make things or an alchemy happen’ sounds like it could be automatic-yoga whereby bandhas/energetic locks or bodypostures or breathing patterns or whatever can arise without any conscious ,at least ,volition of one’s own.This is invaribaly a good sign knowing things are happening providing one does respond by moving forward with caution and self-pacing appropriately one’s openings…
This in particular sounds like it may refer to a kind of dynamic uddiyana bandha often combined with breathing too although it does’nt have to be in sync ;you could be doing ujjayi breath.You can get this say if you practice a dynamic vinyasa or ashtanga-type practice.
You don’t want to be stuck in Ida & Pingala; this is bad but can be remedied like anything with the right approach ideally a tailored one. All yogic practices are about finding greater balance.You could lie down as mentioned say if one of the nostrils was not flowing or stuck and then carry on with your practice whther it is nadi shodhana(alternative nostil breathing, I’d recommend this one with equal counts in each nostril alternately),karma yoga,raja yoga or whatever.
Shiva/shakti, inner outer life,ida/pingala --it is all about balancing or merging opposites to precipitate awakening of sushumna as well as the merging of inner silence and energetic conductivity and this will manifest in these various ways or aspects.
Lieing on one’s side can be done if you really are stuck in one nostril.And after say ten minutes you should be able to tell that the opposite nostril is flowing.There is another method with one arm under the armpit but I’m not sure if it is as effective. Besides one merely has to lie on the ground with this method.If your nostrils and the flow is balanced enough then you can commence already with alternate nostril breathing. But you must practice religously to bring about real lasting change. If you were really committed you could do it all every day ,every waking moment.But you still have to engage with the world now and again,so pace yourself and balance your life out, inner & outer.The real lesson or hidden key behind the balance of ida & pingala is actually balancing one’s inner & outer life out but one is’nt always told that.The Upanishads warns that focusing exclusively on one alone leads to darkness and delusion but that the balancing of the two leads to light.I really think this is a pertinent lesson or point worth bearing out.The suggesstion is one can be too absorbed in the inner practice but one can also be too absorbed in worldly living, i.e go the other way. So in conclusion practices or (unconscious) living of any kind could inadvertently and conceivably stoke both.The trick and aim of all practices is always balance.I tend to associate the mind with ida-stillness and the body with pingala,energetic movement,introvertedness versus extrovertedness but even that is probably just an oversimplifcation. Energetically they are of course opposites and finding balance long-term will awaken sushumna safely and for good.
The suggestion here is combine the right understanding with the spiritual knowledge or tool-base and you are off on the right foot.
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This is what i would prescribe for what you mention;-
Lie one one’s left side for 10 mins until one’s right pingala nostril is open and flowing.Then assume a seat,i.e sit cross legged upright ,relaxed and commence alternate nostril for whatever capacity you find comfrortable. A suggesstion if a range of a 15-to twnety count. If you can do a few cycles without gasping and breathing very slowly and carefully then you have a comfortable range. You must find that range yourself .The trick is make your breaths slow and elongate them,steady wins the race but it should’nt be too diffcult.The breath will be controlled if the mind is also steady so try to concentrate just on attaining your count each way. I tend to use twenty but that might differ for you. Like i said you must be able to get through a few cycles at least without gasping or falling short on the switch.
This practice is a panacea for imbalance and should’nt really be missing from any wise yogi’s toolset. 
