Have you ever bent over in the shower? No wait....best I could find:
sneak (v.) Look up sneak at Dictionary.com
1560 (implied in sneakish), perhaps from some dial. survival of M.E. sniken "to creep, crawl," related to O.E. snican "to desire, reach for sneakily," from P.Gmc. *sneikanan, which is related to the root of snake (q.v.). The noun meaning "a sneaking person" is first recorded 1643. Sneak-thief first recorded 1859; sneak-preview is from 1938. Sneaky Pete "cheap liquor" is from 1949.
Also, BTW, Sneaky Pete Air Force. They were a platoon section of the US Army 219th Aviation Company ("The Headhunter"), flying the 0-1 Bird Dog in support of CCC in Laos.