As for the narration of Safwan ibn Mehran al-Jammal from Imam Jafar ibn Muhammad Al-Sadiq عليه السلام that He said: "I asked him about the two prostrations of forgetfulness (Sajdat al-Sahw), Imam عليه السلام said: 'If you have made a mistake by reducing something in your prayer, then [perform the prostrations] before the Tasleem. But if you have added something, then [perform the prostrations] after the Tasleem.'"
