The Slippery Dipsy-Doodle was Jankom Pog's name for a starship evasive flight maneuver ordered by Dal R'El ("heading 0, mark 270") to evade the Starfleet armada near Gamma Serpentis, in which the USS Protostar flew directly upwards, and then dropped back downward. (PRO: "Supernova, Part 1")
This maneuver bore the hallmarks of the aircraft maneuver known as the "hammerhead turn" or "stall turn".
Also, the term "dipsy-doodle" is a slang term that means "an act, movement, etc., to confuse, evade, or distract the attention of an opponent or competitor."