1st note that Hyphy sounds a lot like Hyphae
2nd note that hyphae is the word for part of fungal tissue
3rd note that fungal tissue = mushrooms
4th -- mushrooms = shrooms = drugs taken for their hallucinogenic effects.
Therefore, it can be concluded that hyphy can also be used as a term to describe activity involving the consumption of shrooms for hallucinogenic effects.
"Dude hook it up with some of that hyphy I want to get GOne"