HR & 178-bplatoon are spot on.

While alum requires wetting prior to use, there is absolutely nothing wrong with applying aftershave on a drier face. However, traditional recs have been along these lines:
1) pour a teaspoon of AS into palm
2) rub palms together for 1-2 sec
3) hold palms apart for 2-3 sec
4) apply to damp face in blah blah motion...
Why the big ritual? To allow enough alcohol to evaporate so that the user may benefit from the fragrance, emollients & antiseptic with minimal discomfort. The amount of alcohol per "splash"
far exceeds that which is needed for antiseptic skin benefits. The relatively high alcohol content is because alcohol also serves as a solvent for the fragrance, as well as an inexpensive preservative (historically).
While the emphasis for aftershaves in recent decades has been on skin care & scent, the antiseptic property of AS was very important in the past (RIP Lord Carnarvon

). I suspect that the alcohol content of AS "back in the day" was far greater than it is now, making the palm-rub-wet face ritual more critical to enjoying a scream-free post-shave

. After all, if it were too painful, most men would've skipped the step...
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