trip sitter

Etymology
Of. Attested from the 20th century; see quotations below.

Noun

 * 1)  A person who watches over a person who is using drugs.

Usage notes
A trip sitter does not use drugs while watching over another. Trip sitters are most often associated with the use of psychedelic or similarly psychoactive drugs. The trip sitter may watch to ensure safety, or on some occasions serve as an active guide to the user's experience.