He heard the Messenger of Allah (ﷺ) say: "When a person prostrates, seven parts of his body prostrate with him: his forehead, his two hands, his two knees and his two feet."
Sunan an-Nasa'i Book 12, Hadith 71
← Previous Hadith "The Prophet (ﷺ) was commanded to prostrate on seven-and he was forbidden to tuck up his hair and garment-on his hands, his knees, the edges of his feet." Sufyan said: "Ibn Tawus said to us: 'He put his hand on his forehead and moved it down to his nose and said: This one thing.'"

Sunan an-Nasa'i Book 12, Hadith 70 Next Hadith → "I noticed the Messenger of Allah (ﷺ) was missing one night, and I found him when he was prostrating with his feet held upright, and he was saying: 'Allahumma, inni a'udhu biridaka min sakhatik, wa bimu'afatika min 'uqubatik, wa bika minka la uhsi thana'an 'alaika anta kama athnaita 'ala nafsik (O Allah, I seek refuge with Your pleasure from Your wrath, in Your forgiveness from Your punishment and in You from You. I cannot praise You enough, You are as You have praised Yourself.)"

Sunan an-Nasa'i Book 12, Hadith 72