To die by jumping in front of an oncoming train. Comes from a combination of New York City subway code for "person under train" (12-9) and shorthand for "yourself" ("12-9 yourself"). Suggestion of how a person "ought to be killed" when one is annoyed with the other person. Similar in meaning to DIAF and DIAT. In other words: "shut up".
by New Brunswick Station April 11, 2006
To die by jumping in front of an oncoming train. Comes from a combination of New York City subway code for "person under train" (12-9) and shorthand for "yourself" ("12-9 yourself"). Suggestion of how a person "ought to be killed" when one is annoyed with the other person. Similar in meaning to DIAF and DIAT. In other words: "shut up".
by New Brunswick Station (subchat) March 22, 2006