hi roderick,
from what i understand, kundalini is latent spiritual energy that resides dormant at the base of the spine until the 'awakening'. i believe any lifechanging experience, pleasant or unpleasant can initiate the stirring of this energy. it seems to culminate in spiritual physical sexual and mindal bliss when it finally traverses all of the chakras, completing the circuit that expands the persons conciousness. your work with the key sound/sexual energy is truly a path that leads to that opening. for myself, a traumatic, intense, life event over 20 years ago initiated my kundalini, and fortunately, i was able to work through the situation and redirect the path towards healing and fulfillment. ksmo and other tools were indispensible aids to this work. and so by working WITH the energy, one can find bliss and liberation, no matter where one started.

ah, the chi machine, what would i do without it? lol. it sure shakes my energy aboot, almost like a daily recharge and cleanse. stale energy oot, fresh energy in.....

interestingly, i can also relate to your visualization ability. i too often think the key sound and have good luck with that; sometimes saying it is too intense for me. and for some reason at times, i seem to do it better in my head than with my voice! my key sound has never really been consistent, yet to be fully understood.
and as for comfort, sitting up is often good for me. laying down seems to constrict my vocalization a bit.
so once again, thanks for chatting, i wish you all the best in your practise!
cheers angus