ENOfficial
Abdullah b. Shakhkhir reported on the authority of his father that he said: I said prayer with the Messenger of Allah (ﷺ) and saw him spitting and rubbing it off with his shoe.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ الْعَنْبَرِيُّ، حَدَّثَنَا أَبِي، حَدَّثَنَا كَهْمَسٌ، عَنْ يَزِيدَ بْنِ عَبْدِ اللَّهِ بْنِ الشِّخِّيرِ، عَنْ أَبِيهِ، قَالَ صَلَّيْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَرَأَيْتُهُ تَنَخَّعَ فَدَلَكَهَا بِنَعْلِهِ .
sunnah.com