A fire on the inside of my writs to show my wild spirit. I think that would be awesome, but hurt like crazy.
I might get it someday.
Or a rose on the inside of my ankle. My grandmother had one there, and it might be like a tradition.
I would definitely get DFTBA written somewhere I could see it, because I frequently need to be reminded to be awesome. Maybe on the palm of my hand, since that's where I always write notes to myself in pen; or else I would turn the letters into an interesting design/symbol and put it on my left wrist so I could cover it with my watch if I don't want it to show.
That was my exact thought as soon as I saw this thread: "DFTBA!" In fact I was discussing it with my sister earlier. As for where... probably somewhere discrete so it would only show when I wanted it to. :D