You might want to double check, but (and this is all from civilian experiences w/ mail in Korea) first class v priority'll only affect speed. I've had vape mail from the States and China shipped to me with first class and priority and both methods have worked. (Though tracking is always a good idea; I've had other mail that were lost, inc a gift to the now ex. ergh.). For wording, I'd describe it exactly as it is (eg atlantis aspire, drip tip, ipv mini, [maybe not "m16"]). In case of
e-liquid, I'd describe it either as flavoring, essential oils, or the name exactly (eg Thug
juice). There's a chance that it'll slip through the cracks without being charged that obnoxious nicotine tax. That all said, w/r/t APO specifically, I'm not sure.