To consciously and frequently check your pockets for your handheld when you realize you can't feel it or the weight of it in your pocket. PSPs', DSs', cellphones, iPods, etc.
Accompanied with this is Chronic handheld check panic where upon checking the pocket where it was thought to be, but not there one will then tense and begin to rapidly pat down all pockets.
-Paul and Micheal leave a party-
Paul: *Paul reaches into knee pocket and sighs breath of relief after feeling his Droid
Micheal: "Damn man you just checked for your phone like 10 minutes ago"
Paul: "Sorry man, I must have Chronic Handheld Check or something cause I get a bit worried when I can't feel it, and this cost a lot of bread.