The descending energy often feels like a corkscrew or drill. Riding the wave of its revolutions (i.e. jumping on board rather than idly standing by) enables it to descend more deeply and rapidly. I become the corkscrew.
I can feel a similar but smaller ascending corkscrew at the base of my spine. A baby corkscrew. The two seem to be looking for each other.
When the connection is made, it sometimes feels more like the corkscrew/drill/spiral, and sometimes it just feels more like electricity flowing through a now-closed circuit. No doubt this is just me paying attention to different aspects at different times.
Once the connection is made, it is often ambiguous which way the energy is flowing (up or down). My guess is that it's both, but I'm still refining my awareness of that aspect. One thing I know is that there is a greater sense of completeness and less of a need to reach further down or root myself like there was when all I could feel was energy flowing down to my feet and I was wondering where it could go from there. I've found a place to hook it up (the base of my spine) and now the lights can just gradually become brighter, without me also having to figure out where to hook them up.