Is prostration of forgetfulness (sujud al-sahw) obligatory after the salutation (taslim) when there is constant doubt in prayer regarding the number of prostrations and rak'ahs, and is it permissible to spit and seek refuge [in Allah] during bowing (ruku') or prostration (sujud)?

It is not necessary to pay attention to doubts and whispers during prayer; rather, one must disregard them. The prostration of forgetfulness (sujud (definition) al-sahw) is prescribed after the salutation as a recommended act, according to some scholars, as Al-Akhdari said: "And the one afflicted by whispers should cast away the whispers from his heart, and not perform what he doubted, but rather prostrate after the salutation, whether he doubted an increase or a decrease." Seeking refuge (isti'adha) during bowing (rukū') or prostration (sujūd) does not invalidate the prayer, and it is a prescribed remembrance. However, bowing is a place for glorifying Allah, and prostration is a place for supplication, as stated in the hadith (definition): "As for bowing, glorify the Lord, the Exalted and Most High, in it; and as for prostration, strive in supplication therein, for it is more likely that your prayers will be answered." One must not pay attention to doubts and should regularly perform the prostration of forgetfulness after the salutation.