It was narrated that Anas bin Malik said:
“We used to perform prayer with the Prophet ﷺ when it was very hot. When one of us could not place his forehead firmly on the ground, he would spread his garment and prostrate on it.”

حَدَّثَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ بْنِ حَبِيبٍ، حَدَّثَنَا بِشْرُ بْنُ الْمُفَضَّلِ، عَنْ غَالِبٍ الْقَطَّانِ، عَنْ بَكْرِ بْنِ عَبْدِ اللَّهِ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كُنَّا نُصَلِّي مَعَ النَّبِيِّ ـ ﷺ ـ فِي شِدَّةِ الْحَرِّ فَإِذَا لَمْ يَقْدِرْ أَحَدُنَا أَنْ يُمَكِّنَ جَبْهَتَهُ بَسَطَ ثَوْبَهُ فَسَجَدَ عَلَيْهِ .