The Loop Cut tool is similar to Blender’s own Loop Cut and Slide tool, except that this one automatically snaps the resulting loop to surface of the Source object.
Works in Edit Mode, only on existing geometry.
In Edit Mode on your Target object, activate Loop Cut from the toolbar or menu and then Left Click on an edge to insert a new loop. A visualization of the loop cut will be displayed while the tool is active, simply hover over an edge to preview where the cut will be placed.
This tool is best used for adding additional geometry to an existing mesh that already has good mesh flow. For example, you might start by mapping out the essential flow with Polystrips or Polypen, and then adding density with Loop Cut.