When PG/VG is heated into a vapor, it causes the moisture in the surrounding air to condense into the visible vapor like your breath on a cold day. This means you are exhaling a bit more water than when breathing normally and this can cause your mouth and throat to go dry causing a bit of irritation if you don't replace it by drinking something.
As far as vaping caffeine, you can certainly dissolve caffeine into e-liquid, but you'd have to vape an entire 1ml cartridge with 20% caffeine just to get the 200mg in a single cup of coffee...
As far as vaping caffeine, you can certainly dissolve caffeine into e-liquid, but you'd have to vape an entire 1ml cartridge with 20% caffeine just to get the 200mg in a single cup of coffee...