Tummo & Photo voltaic Plexus Vibration

How do I “do” tummo?

I’ve a very well-trained photo voltaic plexus, having skilled it for somewhat over 6 years. (was initially unaware what I used to be doing, however stored doing it). My chest has been experiencing robust vibrations these days, seemingly linked to utilization of my photo voltaic plexus. Maybe it is as a result of I am holding in “kiais”? I at the moment cannot produce kiais merely do to schedule and placement. How can I repair this?