A person who feels the need to make sure absolutely everyone knows it's THEIR birthday. These people will constantly remind everyone they make eye contact with, and count down through their facebook statuses several days in advance. Even though everyone has a birthday, they feel that theirs is somehow equivalent to a national holiday.

Birthday tools can easily be spotted by dramatic ensembles, including fluffy tiaras, an excessive amount of balloons, cakes, etc.
Birthday tool: ZOMG MY BIRTHDAY IS IN 6 DAYS!!!!1!!!1!
Normal Person: ...Cool.

on actual date of birthday:
Birthday tool: GUESS WHAT YOU GUYS?! TODAY'S MY BIRTHDAY!!!!!
Normal person: Too bad you announced that 8 times already.
by i.have.no.name. November 4, 2009
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