

If you like milk there’s no such thing as a replacement. Only milk tastes like milk. The other things that have milk in the name taste like whatever they’re made from (not milk).
That being said, pretty much any liquid should work, though the bubbles may not last. Also for something like mercury you may need an air compressor and a much more durable “straw”.
As someone who loves milk and hates coconut, that seems impossible. You do you, but I’ll stick with the real stuff.