It is sunnah to sit “spread out” between the two prostrations (to put the left foot down and to sit upon it and to keep the right foot upright with the toes pointing toward the qiblah). ‘Aishah reported that the Prophet would lay out his left foot and keep his right foot upright. (Related by al-Bukhari and Muslim.) Ibn ‘Umar reported that it is from the sunnah to keep the right foot upright, with its toes pointing toward the qiblah, and to sit upon the left foot. (Related by an-Nasa’i.) Reported Nafa’, “When Ibn ‘Umar prayed, he would face the qiblah, even his shoes.” (Reported by al-Athram.) In the hadith of Abu Humaid, in which he described the prayer of the Prophet, he stated, “Then he would lay down his left foot and sit upon it until all of his bones were in place, and then he would go to make the prostration (again).” (Related by Ahmad, Abu Dawud, and at-Tirmizhi who classified it as sahih.)
It has also been related that ifa’a (laying out both feet and sitting upon one’s heels) is a preferred act. Comments Abu ‘Ubaidah, “This is the statement of the people of hadith.” Abu az-Zubair related that he heard Tawus say, “We asked Ibn ‘Abbas about ifa’a, and he said, ‘It is sunnah to do so.’ We said, ‘We think it to be too harsh for the man.’ He said, ‘It is a sunnah of your Prophet, upon whom be peace.” (Related by Muslim.)
Ibn ‘Umar reported that when the Prophet rose from the first prostration, he would sit upon his toes. He used to say, “That is from the sunnah.” Reported Tawus, “I saw the ‘Abdullahs (‘Abdullah ibn ‘Abbas, ‘Abdullah ibn ‘Umar and ‘Abdullah ibn az-Zubair) sitting with their feet laid flat.” The last two reports were related by al-Baihaqi. Talking of its authenticity, Ibn Hajr says, “Its chain is sound.”
Concerning iqa ‘a sitting with the buttocks on the ground and with the thighs straight on the ground–it is disliked by all scholars. Said Abu Hurairah, “The Prophet prohibited us from three things: pecking like a rooster (making the prostration very quickly), sitting like a dog (iqa ‘a), and not turning one’s whole head like a fox.” This is related by Ahmad, al-Baihaqi, at-Tabarani and Abu Tala with a hassan chain. It is preferred for the one who is sitting between the two prostrations to put his right hand on his right thigh and his left hand on his left thigh with the fingers stretched out and directed toward the qiblah. The fingers should be slightly separated and should not go beyond the knees.