To ingest mushrooms, MDMA, and LSD in the same sitting.
See also Hippie Flip and Candy Flip, and combine the two.
>Did you guys Mega Flip?
>Yeah, we let our strips of acid dissolve, then we ate a couple molly pills each, and added some mushroom chocolates. I was so fuckin high, I thought my brain was gonna melt, but like, in the best way.