Short for "Douche bag jar". Popularized by the 2011 show "New Girl" starring Zooey Deschanel, the douche bag jar is a jar where money is placed when a male does something douchey and someone else (male or female) calls on them to place money in there by saying "douche bag jar."
DBJ was coined at NYU.
Girl #1- I've been told that I look like Eva Mendez before.
Boy- HAHHAHAHA. Psh. You wish.
Girl #2- DBJ
Boy- (puts a dollar in the DBJ)