So, fun fact. You're not the arbiter of what's true or not. There's a whole load of what other people consider to be 'true' that don't make sense to me sure, like this case being a literal event. People tormented in flames are not capable of coherent or eloquent speech for starters. If they somehow were, they wouldn't ask for a drop of water for their tongue for what should be obvious reasons but rather a waterfall, a fire extinguisher or anything else to put the whole fire out. Put it in perspective. If you were in a friends house say and were feeling thirsty (with nary a fire going except the normal house heating) would you ask for a drop of water for your tongue or a glass of juice or whatnot?
I'll stick with the rational side that regard this as symbolic and you can do as you like.
Kind regards etc...