On Pins And Needles Meaning

(idiomatic) Feeling sharp anticipation or anxiety; in a state of suspense.

Example: 1889, Mark Twain, A Connecticut Yankee in King Arthur's Court, ch. 6:
  Merlin hesitated a moment or two, and I was on pins and needles during that little while.
1923, Hugh Lofting, The Voyages of Doctor Dolittle, part 5, ch. 1:
  I was on pins and needles of expectation and curiosity.