During the witchcraft persecutions in Europe, inquisitors were said to have sometimes put an accused witch in a bag, which was then strung up over the limb of a tree and set swinging. When witches learned about this punishment they experimented with it themselves and found that the sensory deprivation or confusion of senses it caused induced hallucinatory experiences. A similar technique has long been used by sha-mans and dervishes and is sometimes known as "dervish dangling." It involves being suspended by a rope tied around the waist.
Modern researchers have followed up on this insight and developed, among other devices, the ASCID (Altered States of Consciousness Induction Device). The ASCID was devised by Robert Masters and Jean Houston of the Foundation for Mind Research. This technological-age witches' cradle is a metal swing in which the subject stands while blindfolded and wearing earplugs. The motion of the swing exaggerates the slightest movement of the occupant. Profoundly altered states of consciousness involving hallucinatory visions and sensations often take place within 20 minutes.
"Witches' Cradle." Encyclopedia of Occultism and Parapsychology. . Encyclopedia.com. (April 19, 2018). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/witches-cradle
"Witches' Cradle." Encyclopedia of Occultism and Parapsychology. . Retrieved April 19, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/witches-cradle