when "dragging the wet mop" ( Love the feel of that btw)...
from the delivery position (hands approx over right thigh, shaft horizontal & parallel to target line)..
as "you" the golfer sees it as you look down..... what direction are you dragging the mop in?...parallel to the target line?.... slightly in to out...slightly out to in?... or just good old plane & simple (no pun intended honest)...simply down the plane line (ie when going down the plane then it will always be slightly in-to-out)... until you cant go down(and out) anymore..and it naturally starts to come back "in" ?