The Collaborative International Dictionary of English v.0.48:

Piddle \Pid"dle\, v. i. [imp. & p. p. Piddled; p. pr. & vb. n.
   Piddling.] [Cf. dial. Sw. pittla to keep picking at, Sw.
   peta to pick.]
   1. To deal in trifles; to concern one's self with trivial
      matters rather than with those that are important.
      --Ascham.
      [1913 Webster]

   2. To be squeamishly nice about one's food. --Swift.
      [1913 Webster]

   3. To urinate; -- child's word.
      [1913 Webster]