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1.
A fat joint smoked at midnight on one's birthday
Happy birthjay! Let's smoke this shit.
by lilKnicky January 06, 2013
 
2.
n. A blowjob given/received on one's birthday
Male: C'mon baby it's my Birthday!
Partner: I'll give you a Birthjay and no more.
by MightyKongHasWoken33 January 24, 2012