I've found that drinking alcohol tends to prevent vapors tongue from forming. Maybe it's just me, but I actually put it to the test a few nights ago. I was drinking water all day and chain vaping a new flavor mix to test before steeping, took the tank to the bar while we played pool, grabbed a beer (Red Fox - Dark Lager with deep red / caramel color). The chain vaping sort of "numbed" my tongue and the beer cleared it up after just a few sips.
I can't say it'll work for everyone, but when you chain vape, vapers tongue is bound to happen at some point. Especially if you vape the same flavor for any extended period of time.