When you flip a bottle of corona upside down normally, less dense gaseous air slips in and travels to the upturned bottom of the bottle, forcing the more dense liquid beer out.
When you put a bottle of liquid inside another bottle of liquid, the density remains the same. No air is travelling to the upturned bottom of the glass, and so the vacuum keeps the liquid in place. Pull the bottle out, or put a straw into the bottle so that air can slip in, and air immediately starts rushing in.
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