For a right handed golfer hitting a high lob shot, kind of, flop shot on the greens, the grip pressure needs to be very light so you can kind of whip underneath the ball and clip it very high. While if you are playing at a very heavy rough, the grip pressure should be constantly firm to make sure the club doesn’t twist over.
Right Hand Golf Tip: The Right and Constant Grip Pressure for Best Results (Video) - by Peter Finch