Heh, saw this in boingboing, the joy of earwax picking, heh... not really a Japanese thing, I think Asians do it. Well, I definately know that Chinese do it. All you Chinese out there, you must remember your own mom cleaning out your ears. It was one of my favs, it's relaxing as well. I remember letting my aunt do it, and it was not as pleasant! But I still do it. You have to use an ear pick to do the job, the cotton buds won't cut it here. Here are some ear picks for your perusal, just so you don't think it's all made up. Here is some more info on it from wikipedia.
Wierd? Relaxing? Addictive? To me, it's just a nice feeling. Plus you have clean ears to boot (as long as you are carefull, you don't want to pierce your ear drums!!).