in full flow
If an activity is in full flow, it is happening fast and with energy:
Preparations for the event are now in full flow.

[TahlilGaran] Advanced Learner's Dictionary ▲

in full flow
if someone is in full flow, they are busy talking about something and seem likely to continue for a long time
be in full flow
if an activity is in full flow, it is happening fast and with energy

[TahlilGaran] English Idioms Dictionary ▲