I believe the best drill for lag putting is to drop 4 balls in the middle of the putting green. Putt to 12 o’clock 3 o’clock 6 o’clock and 9 o’clock and try to get as close to the fringe as possible without touching it. Establish a point system for 1, 2 and 3 feet from the fringe. I. E. 25 points within 1 foot,15 points within 2 feet and 10 points within 3 feet. Outside of 3 feet is zero points and if you hit the fringe it’s zero points. This will allow you to hit multiple putts with multiple breaks, uphill, and downhill. I hope this drill helps.