The Collaborative International Dictionary of English v.0.48:

Sidle \Si"dle\, v. t. [imp. & p. p. Sidled; p. pr. & vb. n.
   Sidling.] [From Side.]
   To go or move with one side foremost; to move sidewise; as,
   to sidle through a crowd or narrow opening. --Swift.
   [1913 Webster]

         He . . . then sidled close to the astonished girl.
                                                  --Sir W.
                                                  Scott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sidle
    v 1: move unobtrusively or furtively; "The young man began to
         sidle near the pretty girl sitting on the log"
    2: move sideways [syn: sidle, sashay]