OP back at the restaurant at closing and catches the waitress leaving: “Hi, this is awkward, but I wanted to apologize if what I did earlier in the night upset you. I’ve been studying a lot lately and my eyes, uhh, oh no, my eyes, they, crap (starts pulling on eyes while bowing over in pain and letting out high pitch kung fu-like noises of relief) Where are you going? No, I’m not trying to do anything offensive! I swear! You don’t have to run away…”

Idk, I manage to do something similar with just one hand, it doesn't look offensive that way. Just figure out a way to do it without offending anyone, if their hands are too small to use one, then continue using two but stare down into your lap before doing it, not at somebody because that's creepy anyways.