A “flip” is a term generally used to describe a psychedelic in combination with MDMA. For example, a hippie flip is magic mushrooms with MDMA and a Jedi flip is magic mushrooms, LSD, and MDMA.
A Heffter flip is when you take synthetic mescaline with LSD. Mescaline has some attributes that make it similar to MDMA when combined with LSD, but also produces strong psychedelic effects. This is one of the only flips that doesn’t involve MDMA. It’s named after Dr. Heffter’s seminal contribution to the foeld of psychopharmacology, which was the identification of mescaline as the active principle in the peyote cactus.
My friend and I got some synthetic mescaline recently and decided to do a heffter flip while we went hiking. The intensity was incredible, but grounded at the same time.