A planchette is a small, flat, often heart-shaped board used in spiritual practices, typically associated with Ouija boards for communicating with spirits. To use a planchette, place it on a smooth surface with a light touch on top of it. Participants then lightly place their fingers on the planchette while asking a question, allowing it to move freely as it supposedly responds to spiritual energies. It's important to approach this practice with respect and caution, as it can evoke strong emotions and experiences.