Hadith 702
'Aishah (May Allah be pleased with him) reported:
عن عائشة رضي الله عنها قالت: ما رأيت رسول الله صلى الله عليه وسلم مستجمعا قط ضاحكاً حتى ترى منه لهواته، إنما كان يتبسم . ((متفق عليه)) .
I have never seen Messenger of Allah (ﷺ) laughing so heartily that his uvula could be seen. He used to smile only. [Al-Bukhari and Muslim].
In plain words
The Prophet was never seen laughing so hard that the back of his throat showed; he would only smile. His warmth came through in a calm, dignified way.
Reference : Riyad as-Salihin 702 In-book reference : Book 1, Hadith 23