It was narrated from Abu Hurairah that the Messenger of Allah ﷺ said:
“When anyone of you yawns, let him put his hand over his mouth and not make a sound, because Satan laughs at him.”

حَدَّثَنَا مُحَمَّدُ بْنُ الصَّبَّاحِ، أَنْبَأَنَا حَفْصُ بْنُ غِيَاثٍ، عَنْ عَبْدِ اللَّهِ بْنِ سَعِيدٍ الْمَقْبُرِيِّ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ " إِذَا تَثَاءَبَ أَحَدُكُمْ فَلْيَضَعْ يَدَهُ عَلَى فِيهِ وَلاَ يَعْوِي فَإِنَّ الشَّيْطَانَ يَضْحَكُ مِنْهُ " .