That unnerving feeling when something has gone horribly wrong while doing work and your anus tightens up in a
flinching and constipated way. It's a form of panic attack when you realise your life / career just ended and you go into a wild panic to try
rectify the situation before you
get found out.
Boss: While you're updating all the systems, if it goes pear shaped, don't have a
nipsy twitch, just get it fixed!
or
Worker: I hit
the red button instead of
the green one and suddenly felt my nipsy twitch.