The Messenger of Allah ﷺ would sit during the two rak'ahs as though he were on hot stones.I asked, "Until he stood up?"He replied, "That is what is meant."
أخبرنا الهيثم بن أيوب الطالقاني قال حدثنا إبراهيم بن سعد بن إبراهيم بن عبد الرحمن بن عوف قال حدثنا أبي
كان رسول الله ﷺ في الركعتين كأنه على الرضف قلت حتى يقوم قال ذلك يريد
[Its chain is daif] Tirmidhi transmitted it in the Salah, chapter on what has been said regarding the length of sitting in the first two units of prayer, hadith 366, and Abu Dawud in the Salah, chapter on shortening the sitting, hadith 995, from the hadith of Saad bin Ibrahim with this wording, and it is in al-Kubra, hadith 764. Tirmidhi said, "Hasan, except that Abu Ubayda did not hear from his father, meaning it is hasan li-ghayrihi in his view."