When your mom and/or dad lets you practice anal on them as your birthday present as they couldn't afford that new hot wheels playset at walmart
Person 1: Bro My Dad gave me that Birthday Cake and my ball sack still hasn't recovered
Person 2: Bro you're so lucky! all i got for my birthday was a Sex Slave
Birthday debt, is when a friend, or family member forgets to get you a birthday present. The friend or family member is now in debt and has to give you two presents the following year.