Douglas Harper's Etymology Dictionary
Wiktionary
alt. 1 A hole in a vessel, such as a cask, that may be stopped with a bung. 2 (context vulgar slang English) The anus. n. 1 A hole in a vessel, such as a cask, that may be stopped with a bung. 2 (context vulgar slang English) The anus.
Usage examples of "bung-hole".
The barrel was in the barn, resting on its side, the bung-hole neatly plugged, its filling port on top and open.
When he saw a movement behind the unplugged bung-hole, he did it once more.
When the tentacle quickly sketched an oblong around the bung-hole, he obliged.
Then he worked the piece of leather with the hole in it into the bung-hole, flattening it out with his fingers inside the barrel and over the top of the powder to act as a washer so that it covered the powder except for the hole he had cut out.
Edwards inspected the pitch in case it was too hot, then gently poured some on to the marline wound round the portfire in the bung-hole, filling up the circular depression.
Taking up a copper spoon that Hooke had left near the scale (copper did not make sparks), he scooped up a small amount of powder from the bung-hole and began sprinkling it onto one of the scale’s frail golden pans.
Perhaps the other end of the fuse had been plucked from the bung-hole of the powder keg.
One end had fallen from a bung-hole in the lowest row of powder barrels, the other had dropped into the stream which had extinguished the fire.
Taking up the roll of marline he tucked an end between the leather and the inside of the barrel and began to wind it round and round the base of the portfire, as though rewinding a cotton reel, pausing every now and again to push it down until the portfire was a tight fit in the bung-hole, and leaving a shallow depression all round.