I am afraid " Here we go ,check the flow ,, Johnny B...." still says nothing about the sort of flow referred to ;) I don't know the situation and circumstances mentioned in this song. Hopefully someone knows that one!

Hello Kukuann, The flow of what ? It depends in what context it is said. The 'flow' is the act, rate or manner of a flowing substance ( usually a liquid )or the continuous progression of a certain phenomena. ' to check the flow' could mean to control ,restrain or slow the progress of a certain flow or just to examine the flow for accuracy, quality or progress. *In oilfield for example a "flow check" is a test performed to ensure stable well conditions or the integrity of a plug, valve or flow-control device. In most cases, the flow check involves observing stable fluid levels or conditions for a prescribed period.

Yes, we'll need more context here.... On face value, I'd interpret "check the flow" as in "stop the flow" (are we talking about blood flow?). "Check" in this case refers to the chess move where one piece (eg. King or Queen) is limited or fully prevented from moving easily. Apply a tourniquet! :)

what´s the context?