(140) باب الْمُكْثِ بَيْنَ السَّجْدَتَيْنِ
Narrated Thabit:
Anas said, "I will leave no stone unturned in making you offer the prayer as I have seen the Prophet (ﷺ) making us offer it." Anas used to do a thing which I have not seen you doing. He used to stand after the bowing for such a long time that one would think that he had forgotten (the prostrations) and he used to sit in-between the prostrations so long that one would think that he had forgotten the second prostration.
Reference: Sahih al-Bukhari 821
In-book reference: Book 10, Hadith 215
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 12, Hadith 784