Nokia :: N73 - Battery Start Working When Tapping Its Side?

I come with an interesting problem regarding my N73. It is a bit long. Here is a bit of back story:

I have(or had) two Nokia N73 one was a North American model and the other from Japan (called Softbank 705NK). About 2 weeks ago, I gave the North American one to my brother because he was without working phone. Last Thursday the battery in that phone took a dump and needed to be replaced. He turned the phone off to go into a meeting and when he went to turn it back on it would not turn on(It had a full charge on it when shut off). Putting it on a charger did not work. I tried charging the phone up with the other Nokia charger I had and it did not work. Then I tested the battery by putting it into the Japan Market N73 and the battery still did not work. I then put the JDM (Japanese Domestic Market) N73’s battery into his phone and the phone turned on. I also checked both chargers on this phone and both worked on his phone with the JDM N73’s battery. I concluded his battery was dead and gave him my battery and promptly ordered a new battery from Nokia for the JDM N73. (I was not using it anyway at that time)

Here is where it gets interesting, on this past Saturday I decided to try the “dead” N73 battery one last time before I tossed it out and I put it in the JDM N73 and it worked and it charged and performed well under heavy use (i.e. picture taking and surfing the web). Today I put it down and it shuts off (with a full battery). I figure I must have pushed the off button on it and turn it back on. All is well until I slide the camera cover open and it shuts off again. I turn it on a third time and tap the left side (the non side button side) absent minded while pondering something and it turns off a third time. So this time I power it up and tap the spot above the IRDA (on the side without side buttons) and sure enough it shut off. I duplicated this a third time with the same results. I then took the battery cover off and discovered the battery does have some side to side play but looks secure. I was able to get it to shut off with a really hard wiggle but it does not seem to break contact under normal duress.

The shutting off when opening the camera lens cover and the tapping of the side of the phone lead me to think it is a lose battery. This phone never gave me an ounce of trouble with the original OEM battery that came with it and likewise the North American N73 never gave me trouble with the battery(until it died). So why did it start now? Would a battery that is on its last legs be more susceptible to vibration/movement? I will be trying it with the new OEM battery arriving from Nokia (should arrive ether Mon or Tues) to see. Should it turn out to be a loose battery, how does one fix it? Would wrapping a strand or two of electrical tape around the sides of the battery to thicken out the battery fix it or will the old paper on top of the battery help?