Dreamfasting can occur when Gelflings touch. In a dreamfast, memories are communicated to each other in a kind of telepathic memory montage.
In The Dark Crystal, when Kira grabs Jen's hand to help him up, the two become dreamfasted and quickly learn of the other's pasts.
In Legends of the Dark Crystal, Lahr and Neffi are dreamfasted in Volume 1 after both become the only members of their respective villages not taken by the Garthim to the Crystal Castle, and in Volume 2 after Neffi rescues the prisoners and Lahr encounters SkekLach.