The galleons crews sleeping arrangements are closely arranged hammocks slung high from the mess-deck bulkheads. The hammock provides the perfect sleeping platform when at sea as the ships movements are almost cancelled out by the pendulum action of the "swinging hammock".
The duty Bosun's task every morning is to rouse the watch on deck crew from their sleep and ensure that they are all working by the given time.
It was normal practise for a sleeping sailor to be unceremoniously tipped out of his hammock to a rude awakening.
After months at sea, the old sailing ship is in harbour to deliver its cargo and load another. This is an exercise that must be completed as quickly as possible as a ship in harbour is not earning money. Therefore the crew were still required to work long hours with the cargo stowage
But in harbour it would be common place to find both the sailor and his chosen "Lady" asleep in a single hammock.
So now the Bosun would shout loudly "Show A Leg". A leg would appear on both sides of the hammock. The hairy one belonged to the sailor, the smooth one attached to the female.
The Bosun would yank the sailor out of bed, normally leaving the "Lady" to sleep longer.
Hence today we will use the expression "Show a leg" whilst trying to rouse someone from their sleep
Should the Bosun feel a little devilish, he would pull on the ladies leg and be met with a shriek. The force applied would be insufficient to pull the female out of the hammock, so the Bosun would laugh and say "Go back to sleep I was only pulling your leg"
Now where have I heard that one before?
Not a lot of people knows that.... as Michael Caine would say
Odd how many expressions we have from our Naval past