I thought that it was meant to mean
Side to side
IE when the Me110s came up under lets say a bomber who was making gentle side to side movements along the track so as not to be in a straight flight path the Me110 night fighter would mimic the side to side motion and once he had or flow and ebb and once he had got the flow and ebb let go with his upward facing gun.
As massive blind spot on a lot of RAF bombers.
….just a little off topic , the wonderful author William Green always referred to them as a Bf 110 ??