(8) باب الْمُصَلِّي يُنَاجِي رَبَّهُ عَزَّ وَجَلَّ
Narrated Anas:
The Prophet (ﷺ) said, "Do the prostration properly and do not put your forearms flat with elbows touching the ground like a dog. And if you want to spit, do not spit in front, nor to the right for the person in prayer is speaking in private to his Lord."
Reference: Sahih al-Bukhari 532
In-book reference: Book 9, Hadith 11
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 10, Hadith 509