I’m pretty sure that licking pure magnesium would make your tongue explode too.
Definitely not licking pure lithium, sodium, or any of the alkali (s-block) metals. My tongue is wet. That shit explodes in water, yo.
Magnesium is fine (see response above). https://invidious.darkness.services/watch?v=Q_4I30Nz_b0 Just don’t vomit on it before you lick it, 'cause it’ll get spicy with acid.
I have elemental magnesium (4 ~50g ingots, I keep it in my library in a barely-sealed ziplock). it’s shelf stable and doesn’t react violently with water. Want me to try licking it and let you know? (hint: at worst it’ll make a minuscule amount of milk of magnesia)
ETA: Would I stick my tongue in pyrophoric magnesium powder? No, and you wouldn’t do that with pyrophoric aluminum or zinc powders, either, but that doesn’t stop me from using (or licking) alumnum foil. Proof: https://invidious.darkness.services/watch?v=Q_4I30Nz_b0