What's to explain? You pull the trigger, the gun bucks in recoil with the grip rolling in your hand. You reach up with your thumb while the gun is still raised and cock the hammer on the way down.
With your pinky under the grip, the gun rolls right back to where it was before. Keep your pinky under the grip when you pull the trigger again. The trick is
not to try to prevent the gun from moving in the hand, allow it to. Don't grip it with a death grip, allow it to move. Those are full house 45 Colt Black Powder loads, they are not mouse farts. Allowing the gun to roll helps shoot it consistently. No regripping is necessary, just let it roll back to where it was.
Repeat four more times.