A fork of Rural Dictionary
The expression used to blame someone else for something. Taken from an old Cingular commercial.
Mom: Stephy!
Girl: WU?
Mom: Your cell phone bill is what's up, all of this texting!
Girl: OMGINBD
Mom: It is a big deal! Who are you texting 50 times a day?
Girl: IDKMYBFFJILL
Mom: Tell your BFF Jill that I'm taking away your phone.
Girl: TISNF!
Mom: Me paying this bill, that's what's S, dang F!