Bricks 'n stuff
Well, first of all let me start off with some advice not to get too carried away with the brick thing because practicing all the time on heavy, immovable objects will slow you down a bit and dull your power in chi sau.
My sifu first taught me the brick thing to be used as a demo piece which highlights the difference between relaxed “shock” power and that of “hard” muscular power (proving that you don’t have to be a football lineman in order to do damage), and of course I thought it was cool and started smacking bricks every chance I got. Thing is, after a while I started to notice that my reaction time when I practiced chi sau with my kung fu brothers was getting a little sluggish. So, it’s fun to do but keep it balanced with your regular training. About the only time I ever touch a brick anymore is when I’m doing a demo (which is infrequent).
Anyway, a good drill to practice subhydroshock power (and brick-breaking if that’s your inclination) is to take your standard issue wallbag, put it on something about waist height (on a table, or you can put it on something lower if you kneel) and practice dropping your palm onto the bag. What you do is start with your arm extended in front of you at eye level, completely relax, and drop your arm (without any added acceleration on your part - just let gravity bring it down), letting the full surface area of you palm impact on the bag - trying to feel a sharp stinging impact on the bottom of your hand. This drill trains your palm strikes from a completely relaxed state and helps develop the requisite power.
After you get the right feel in your hands from the “dropping” drill, then you can add in a short elbow acceleration which whips your arm down into the wallbag. Make sure you aren’t trying to hit the bag “hard”, but are still maintaning complete relaxation to develop the “shock” effect. The feel in your arms is almost like you are “throwing” your arm down and just letting it go, rather than trying to shove it down with your muscles.
After this you can go buy yourself one of those flat grey paving bricks, put it on some supports, slap a phonebook on top, and start the “drop” drill all over again until you feel comfortably relaxed. Then start in with some elbow acceleration to feel the shock impact when you hit. To send the shockwave through the book and into the brick you just need to maintain some elbow pressure downward upon impact so your palm doesn’t just bounce off the book.
When you get the feel of the proper elbow acceleration, feel the shock power in your palm, and maintain your elbow pressure so you don’t bounce, take a deep breath and go for full acceleration. You should be able to do the job.
Explaining this is kind of hard. If I was in front of you I could take two minutes to explain it to you, show you the motion a couple of times, have you take a practice shot, give you a pointer, and have you laying the smack down right away. It really doesn’t take that much training to accomplish.
Now as far as translating this to fighting:
Working the wallbag exercises will do amazing things for your speed and power, believe it or not. When you practice chi sau you want to use the same kind of relaxed elbow acceleration in all of your arm movements with the same maintanence of elbow pressure upon impact when you’re striking. You’ll notice that your “soft” strikes will have a funny split second delay before they vibrate in and start wreaking havok.

Not to tire of learning is wisdom;
Not to weary of teaching is benevolence.
– Tzu-kung