Lag is the part of the swing that has the hands leading the swing into impact to develop greater power and control in the swing
Keeping your right hand on the grip in a neutral positoin allows the clubface to come into impact square, turning that hand in either direction will cause the face to close or open at the top of the backswing
Hitting a guaranteed draw every time, to get around things like a tree, is simply learning how to set up for the shot with a closed clubface, closed stance, do not turn your body too early and allow your forearms to rotate through the shot more