1) Act crabby 2) Act like a crab 3) Advance coyly 4) Advance crabbily 5) Advance furtively 6) Approach furtively 7) Approach sideways 8) Approach sneakily 9) Crab walk 10) Crablike move 11) Crabwalk 12) Creep along, crab-style 13) Creep like a crab 14) Edge 15) Edge along 16) Edge along slowly 17) Edge forward 1) Edge 2) Inch 
• (v. t.) To go or move with one side foremost; to move sidewise; as, to sidle through a crowd or narrow opening.
a threatening posture where one rat (often but not always the dominant one) approaches another rat sideways , with his back strongly arched, and gets close or makes contact with the other rat.
Si'dle transitive verb [ imperfect & past participle Sidled ; present participle & verbal noun Sidling .] [ From Side .] To go or move with one side foremost; to move sidewise; as, to sidle through a crowd or narrow opening....
[v] - move unobtrusively or furtively 2. [v] - move sideways