It was narrated that Jabir bin Samurah said:"I prayed with the Messenger of Allah (ﷺ) and when we said the salam we used to gesture with our hands: 'Asalamu alaykum wa rahmatullah (peace be upon, peace be upon you).' The Messenger of Allah (ﷺ) looked at us and said: 'What is the matter with you, pointing with your hands as if they are the tails of wild horses? When any one of you says the salam, let him turn to his companions and not gesture with his hand.'"
أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، قَالَ حَدَّثَنَا إِسْرَائِيلُ، عَنْ فُرَاتٍ الْقَزَّازِ، عَنْ عُبَيْدِ اللَّهِ، - وَهُوَ ابْنُ الْقِبْطِيَّةِ - عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ صَلَّيْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَكُنَّا إِذَا سَلَّمْنَا قُلْنَا بِأَيْدِينَا السَّلاَمُ عَلَيْكُمُ السَّلاَمُ عَلَيْكُمْ - قَالَ - فَنَظَرَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ " مَا شَأْنُكُمْ تُشِيرُونَ بِأَيْدِيكُمْ كَأَنَّهَا أَذْنَابُ خَيْلٍ شُمْسٍ إِذَا سَلَّمَ أَحَدُكُمْ فَلْيَلْتَفِتْ إِلَى صَاحِبِهِ وَلاَ يُومِئْ بِيَدِهِ " .
Nesai
The Book of Forgetfulness (In Prayer) • Hadith 1326