Acronym for 'Tonka Fucking Tonka' Like FFS, the word is used to express feelings of annoyance and distress, however, the word 'Tonka' comes from an ancient tribal language and so it is a much more primitave way to show such feelings.
eg1. Jim: TFT! I dropped my ice cream
eg1. Carly: BTW, i can't come to this party of yours.