the.com/pins and needles

The feeling of blood remembering where it left its keys.

means That prickling, tingling numbness in a limb that's been compressed and is now waking back up, or figuratively, the state of nervous, anxious anticipation while waiting for something.

from The phrase surfaces in English by the 19th century, a plainly sensory coinage — the sensation of returning circulation really does feel like a scatter of small sharp pricks, as if your foot had been reupholstered with a pincushion. The figurative sense, 'on pins and needles' meaning anxiously waiting, grew naturally alongside it: both describe a restless, can't-sit-still discomfort, whether in the body or the mind.

medical name
paresthesia, from the Greek for abnormal sensation
actual cause
nerves firing randomly as circulation returns
not dangerous
usually gone within minutes, unlike your anxiety about it
idiom sense
anticipation so sharp it borrows the same word
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