Set the shaft at an angle to build your trail hand grip
Rather than gripping with the club low, the coach sets the club up at an angle - he says roughly 90 to 120 degrees - before forming the trail hand. He explains that keeping the shaft down makes it easy to roll the hand under into a poor grip, while setting an angle makes that virtually impossible because the hand won't fit that way.
Channel: PorzakGolf
Watch official source at 1:34