to insure that no one sits in your seat for five minutes if you get up (to throw out
trash, go to the bathroom, grab some
chips, etc.)
it literally means that you call your seat for five minutes; if you call fives, get up, and come back
ten minutes later, your seat is liable to be taken
a very
good system to avoid fights, bad feelings, and general undesirable situations
there is no such thing as 'calling tens' or any number other than five; this is because five minutes is a reasonable amount of time to be gone for
"I call
fives, as I'm just getting a soda from downstairs. If anyone takes my seat, I
will personally kick you in the
nuts until you bleed."