The Prophet ﷺ said, "Be straight in the prostrations and none of you should put his forearms on the ground (in the prostration) like a dog." (Using translation from Bukhārī 822)
عَنِ النَّبِيِّ ﷺ أَنَّهُ قَالَ اعْتَدِلُوا فِي السُّجُودِ وَلَا يَبْسُطْ أَحَدُكُمْ ذِرَاعَيْهِ انْبِسَاطَ الْكَلْبِ