Asshole, bung-hole.

Derived from the use of "stopple" as synonym of "stopper."
"...it was Shrove Tuesday even as 'tis now - gave me my breakfast, and swore then by the stopple of my tankard if ever I came to be Lord Mayor of London..." - The Shoemakers' Holiday by Thomas Dekker

"Quit being a stopple, Ken!"
by dj_gwen April 9, 2006
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