How Is it that someone amongst you stands before his Lord and then spits out in front of Him? Does any one of you like that he should be made to stand in front of someone and then spit at his face? So when any one of you spits, he must spit on his left side under his foot. But if he does not find (space to spit) he should do like this. Qasim (one of the narrators) spat in his cloth and then folded it and rubbed it. (Using translation from Muslim 550a)
أَنَّ رَسُولَ اللهِ ﷺ رَأَى نُخَامَةً فِي قِبْلَةِ الْمَسْجِدِ فَأَقْبَلَ عَلَى النَّاسِ فَقَالَ مَا بَالُ أَحَدِكُمْ يَقُومُ مُسْتَقْبِلَ رَبِّهِ فَيَتَنَخَّعُ أَمَامَهُ؟ أَيُحِبُّ أَحَدُكُمْ أَنْ يُسْتَقْبَلَ فَيُتَنَخَّعَ فِي وَجْهِهِ؟ إِذَا تَنَخَّعَ أَحَدُكُمْ فَلْيَتَنَخَّعْ عَنْ يَسَارِهِ أَوْ تَحْتَ قَدَمِهِ فَإِنْ لَمْ يَجِدْ فَلْيَتْفُلْ هَكَذَا فِي ثَوْبِهِ فَوَصَفَ الْقَاسِمُ فَتَفَلَ فِي ثَوْبِهِ ثُمَّ مَسْحَ بَعْضَهُ بِبَعْضٍ