The Circumstances of the Prostration for Forgetfulness

Question:
Tell me about the prostration for forgetfulness in prayer, regarding adding to the prayer and regarding subtracting from the prayer.

Answer:
The prostration for forgetfulness is permissible before the closing salam and after the closing salam in all cases of forgetfulness. If one prostrates before the salam, that is sufficient, and if one prostrates after the salam, that is sufficient. However, the better option is to do it before the salam; that is the best, except in two cases:
The first is when one acts based on his predominant suspicion. If he doubts whether he prayed two or three rak'ahs, meaning he is not sure if he prayed two or three, and he acts on his predominant suspicion—meaning his predominant suspicion is that he prayed two—he must complete the prayer, or if his predominant suspicion is that he prayed three, he completes the prayer. In this case, it is better for his prostration to be after the salam if he acted on his predominant suspicion.
The second case is when he says the salam due to a subtraction. He says the salam after two rak'ahs, or after three rak'ahs of a four-rak'ah prayer, forgetting, and then he realizes and completes the prayer. In this case, it is better for the prostration for forgetfulness to be after the salam. In all other cases, the prostration before the salam is better.
In any case, his prostration before the salam or after the salam in all these scenarios is valid, and praise be to Allah. Yes.

The presenter: May Allah reward you with good, and may He do you good.