To be the best of something that there is. To be great and
extremely, utterly wonderful. Not just fantastic, not just
fantastical, but fanfuckingtastical. The epitome of
fantasticness. It can also be used in a sarcastic manner.
This is
the most fanfuckingtastical day of my life!
Sarcastic example: Oh that's just fanfuckingtastical, I'm late to work, haven't eaten
breakfast and my tire is flat. Fanfuckingtastical!