Here I explain my technique of picking open a Lockwood Assa Abloy 334M45 padlock.
Lockood's are full of "spool" security driver pins (which cause counter-rotation when picking), and also "tapered" key pins, where the end of the key pins that meet the driver pins are have a thin bit of tapering (where it slowly reduces in diameter - see the picture in the video).
The tapering on the key pins makes it very easy to overset (lift too high) a key pin, and so that's why you have to release tension momentarily to enable the key pin to drop back below the shear line.

Jack Fox
@jackfoxlock