My last practical idea was of course shot down in flames, so before i say anything more, i just want to stress that this assumes informed consent, is self-administered or part of a fantasy. Whatever floats your boat.
We all know about diet coke and mentos. The most important active ingredient in mentos from that perspective seems to be gum Arabic, which provides multiple nucleation sites for the release of dissolved carbon dioxide. However, if it's swallowed, it tends to lose those sites due to
So, this is my proposal.
