"Tapping The Admiral" is slang for drinking on the QT
. The origin story
: When Admiral Lord Nelson
was killed at Trafalgar
, his body was preserved
in a cask
for the voyage home -- a primitive but perfectly servicable embalmment
Upon return to port, it was discovered that the keg was empty save for the body, for the sailors had surreptitiously drained the grog off, measure by measure.