Green’s Dictionary of Slang

the comforting of someone who is having a bad experience, usu. through injudicious use of drugs, esp. a hallucinogen; also attrib.

1995		B. Wallace ‘How to talk someone down (ARRRT technique)’ on Erowid.org 🌐 Two cautions when using the ARRRT talk-down technique.
a.2003		C. O’Hagan ‘Drug Services and legal boundaries’ on DrugText.org 🌐 Release would go along, the crew would move the whole office (usually in a borrowed van!) and go to a psychedelic all-nighter or festival and set up either a trip room or a trip tent featuring the Release name. In there, people would be given a ‘talkdown’, a bit of space to chill out.