It wasnarrated that Mu'aiqib said:
"The Messenger of Allah (ﷺ)said,concerning smoothing the pebbles during prayer: 'If you must dothat, then do it only once.'" (ES)
English reference (ES): Vol. 1, Book 5, Hadith 1026 (ES)
Arabic reference (ES): Book 5, Hadith 1079 (ES)