As a late night developer, I drink lot's of e-drinks, and w/e works.
However, (believe it or not) it is common practice for a developer (when falling asleep) to bite down on their tongue (not too hard).
It is recognized that a small amount of pain that is self-inflicted is possibly one of the silliest yet most effective ways to stay awake, again, be careful though, a small bite, not to much, if you break skin, see a doctor & a psychiatric.
Candy, Iced Tea (xtra sweet) can work for me as well sometimes, but it doesn't last long.
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