Flow for me is the ability to string multiple different shots together with out ever needing to trap the ball, do a dead flip etc. Combo'ing shots together.
STTNG - Alpha ramp to Beta Ramp To left orbit to Delta ramp to Left orbit to Delta, rinse and repeat - ball never stops.
ToM - center stairs, center stairs, inside loop, inside loop, right stair case, left orbit, left orbit ........ball never stops