LSD fakes?

I'll put my vote in for the metallic feel in the mouth (not even really a taste), but otherwise not detectable by me...."that feeling in your mouth."
Maybe some people can taste it and others can't.
Definitely had completely tasteless liquid before.

(When I just tasted some samples of regular paper it really didn't have much taste. But, I didn't try any with ink on it.)

I think it's a matter of the level of bitterness maybe. If it tastes like you chewed a Tylenol or something, I think it's probably DOx or Bromo df if it has some effect.

I've never (or others I've been with) have had it take 2 hours to take effect...but maybe for some it does. If it took 2 hours for everyone who took a particular kind and it tasted bitter, I'd be more than a little suspicious.