Man, where is catbirdseat when you need him??
You can't really have a glass of fluoride... fluoride is a negative ion that forms salts with positive ions. When it's in water it's part of a dissolved compound like sodium fluoride.
To be clear, we are not talking about the element fluorine, which is a gas at room temperature and is indeed very toxic. The chemical properties of fluorine and fluoride are very different.
Anyway, maybe you know something I don't, please educate me about the well-known toxicity of fluoride.