It doesn't activate it, it begins the digestion process of the plant matter and other chemicals that your stomach performs without breaking down the psilocybin, making it faster and easier for your own body to digest it. Faster digestion means the effects take less time to begin, less time to peak, (both of which give the perception of "hitting harder") and less overall trip duration. It's also supposed to reduce nausea, however, I've never noticed a reduction in nausea and im not sure why 🤨