What is the evidence for the prostration of gratitude and how is it performed?

Question:
Was the Prophet (peace and blessings be upon him) in prayer when he interceded for his Ummah?

Answer:
It is not in prayer. The prostration of gratitude: a person prostrates even if he is not in a state of ritual purity, according to the correct view. The prostration of gratitude and the prostration of recitation are recommended, even if one is not in a state of ritual purity.
Q: Does one raise the head after the prostration, like the takbir in prayer?
The Shaykh: There is no obligation to say takbir. If he says takbir when prostrating, that is good, if Allah wills, when prostrating.
Q: Is the hadith of Sa'd ibn Abi Waqqas authentic?
The Shaykh: The author did not address it; the author passed over it. But the prostration is established from the Prophet (peace and blessings be upon him) as gratitude.
Q: In a version verified by Shaykh Nasir al-Din al-Albani, it says: The hadith of the prostration is weak in chain and text?
The Shaykh: It needs consideration; because he may have made a mistake, may Allah forgive us and him, he may have made a mistake.
Q: Is the hadith authentic?
The Shaykh: But it has corroborating narrations in another hadith: When a matter comes that pleases him, he prostrates to Allah (peace and blessings be upon him).
Q: Does it have a specific form?
The Shaykh: Like the prostration in prayer. The prostration of recitation and the prostration of gratitude are like the prostration in prayer.
Q: Does one face the qiblah?
The Shaykh: It is better. The Sunnah is to face the qiblah if that is possible.