couldn't your friend do an allergy test or something?
like hold the tiniest little piece of a psilocybe mushroom on her tongue without swallowing and see if there is a reaction.
if not, then swallowing the tiniest little piece and waiting to see what happens.
if nothing, then eating a little more and a little more...always going really slowly.
this is how we would sample potential food sources in the wild, there are few things that would cause deadly reactions in such minute quantities if approached cautiously.
maybe it's not even worth it though....
get a food dehydrator and just dry the cactus, and powder it in a blender.
put into gel caps, or vege caps
, and swallow pills with orange juice.
no tek needed. readily available, and preferable to LSD in my little cave.