In theory, practicing the lower block in Goman (normal ready stance) the left blocking arm is folded to the upper right over the right ear. The folding motion also turns the body slightly to the right. The right arm is wrapped around the left ribs at about one fist away from the body.
The focus of the drill was to ensure that this turning occurs whilst under duress. Not only does the turning of the body present a much smaller target, it allows some deflection of the punch if the oncoming trajectory has not been modified by your block (meaning your block sucked). So if the opponent were to lunge at me with his left arm, I would turn to the left and block his arm from the outside with my right forearm.
Not only does the body rotate, in order to have solidarity in my body movement, I have to exhale. The exhalation allows me to think of creating a small convex in my body in order that I increase the distance between the striking arm and its target.
|That's me doing Chon-ji, Perth, Western Australia|
With a pliable, relaxed, and responsive body I then perform Chon-ji's lower block by dropping my entire body weight like a pile driver on the extended striking arm. This is a method of creating a lot of power without lunging forward. It's related to the 'falling forward' most beginners would use when striking with the lead hand in a 'self defence' situation. However, rather than just dropping one leg, both legs in this case are synchronised and move apart at once. The drop needs to be transmitted into your blocking motion - so some coordination is appreciated.
You cannot be tense and relaxed at the same time. Many people have the overwhelming urge to make a hard style martial art more tense than it should be. There is a lot of rigidity within a hard style martial art, but within this basic framework -- relaxation between techniques is very important. A good training tip is to make sure you are attempting to learn moves whilst being as relaxed as possible.