Ritualistically, ceremonially, i.e.,rites of passage with elders and shamans (guides, therapists, interpreters, usually holding the stash. Hardly ever recreationally like alcohol, khat, marijuana, opium, etc.
Today, however, TPTB fear the insight, expansion of consciousness, and ability to tap into long forgotten and suppressed, inherent and dormant psi capacities. The most practicable and humane breakthroughs are in treating mental trauma like ptsd, which allows the patient to remember and talk through the past traumas without the unpleasant "fight or flight" response or "triggering" effect. In this regard, many here tend to trivialize the expression. I've learned the hard way that one shouldn't overuse the "T" word, despite as much fun as it can be.