Nt
Rancid goat semen.
Liquid Sweet Tarts.
Cough medicine with 16 extra tablespoons of sugar.
Even better with Stoli. Then it tastes like 12 year old cough medicine with 16 extra tablespoons of sugar.
Exactly.
My guess is that it is not designed to simulate any naturally occurring flavor. All energy drinks taste essentially the same to me, and I am guessing that this is just the characteristic taste of a solution of sugar(s) and citric acid. I would imagine that if you simply mixed sucrose, water, and citric acid together without any other coloring or flavor agents, the taste would be more or less identical to Red Bull. The only real answer to your question might be that Red Bull is ‘energy drink flavored’.
I always describe it as Flintstones Chewable vitamins muddled with Robitussin mixed with soda. And bewilderingly colored to look like a urine sample.
There are a few flavors of energy drinks, even multiples within one company. Red Bull tastes like gnu repellant to me, while Full Throttle tastes like liquid gummy worms, only worse.
I drink Monster, but SoBe Adreneline Rush tastes very similar.
Marmite and wee.
Ass
I was expecting an answer more along the lines of “raspberry”.
Vile
Rasberry
Close. Bull. 
AssBerry
Red Bull was originally a Thai “vitamin” tonic - much thicker, not fizzy, and more syrupy.
Therefore I suggest Flintstones Chewable Vitamins is about right.
My mom described it as smelling like my dad’s armpit, so I suppose it might taste the same.
Hate.
It tastes like hate.
Cilantro tastes like hate. Red Bull definitely does not taste like cilantro. I never knew so many people were repulsed by the stuff. I think it’s a little too strong on its own, but quite pleasant-tasting with vodka. That’s why I asked, actually. I was wondering if I could get the same or similar taste somehow without the alcohol.
It tastes like yellow, the same way that NyQuil tastes like green (thanks, Lewis Black!).