How did Salvador Dali make himself hallucinate?

Salvador Dalí used a technique called "slumber with a key" to induce hallucinations. He would sit in a chair while holding a heavy metal key above a plate; as he fell asleep, the key would drop and awaken him, which he believed allowed him to access the subconscious mind. This method aimed to blur the line between dreams and reality, enabling him to capture surreal imagery for his artwork. Dalí's fascination with the subconscious was influenced by Freudian theories, which he sought to explore through his creative process.