It's a figure of speech rather than an idiom. When standing for a long length of time, your own weight can put pressure on the nerves of your legs. It can also put pressure on the blood vessels and restrict normal flow of blood to the nerves. Either way it makes the nerves act erratically.
This is characterised in a loss of feeling or movement in the affected limb, and hence, the limb has 'gone to sleep'.
It's not an idiom because you can figure it out by the context. It means they went bald.
I Went to Sleep was created in 1969.
"Her foot went asleep" refers to her foot feels numb, such as you stop moving it for a long time and it feels weird when you move it, like needles are being pushed through it, but less pain, but it wears off as though it's waking up.
To "go on a fishing expedition" means to attempt to find out information, e.g., "The lawyer went on a fishing expedition to try and discover the facts of the case."
Went under is used to mean they have failed, as in drowning. A business that went under is one that has closed or gone bankrupt.
Jim Stafford. Just Another Pretty Foot album.
because u were thinking of really weird things bfore u went to sleep. LOL! XD
"The bear went to sleep!" in English is L'orso è andato a dormire! in Italian.
Some people sleep on hammocks but some of them sleep on beds but when i went to Mexico i slept on the hammock.
she went on foot
Evey time he went to sleep something bad happend.
The question tag for the sentence "The children went to sleep" would be "didn't they?" Therefore, the complete sentence with the question tag would be: "The children went to sleep, didn't they?" This tag is used to confirm information and reflects that the main clause is in the past tense.