[graedus]

I've never heard or seen it until this moment.

[mywittyname]

I've not heard "tifty" but I've definitely heard the phrase, it's pretty widely used among people under 25 in the midwest.

[code_duck]

The phrase 'thanks for the invite', of course. The acronym TFTI, no, and pronouncing it as 'tifty' or verbalizing the term at all, no.

Of course, all this means is that TFTI is an acronym, which are added to language all the time.