Prayer: Realising Clothing is Usurped During Prayer
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 805
If someone does not know or forgets that his clothing is usurped and realises this during prayers, in the event that something else covers his private parts and he can immediately or without breaking the close succession (muwālāh) – i.e. by maintaining continuity in the prayer – remove the clothing and continue praying, he must do so. If there is nothing else that covers his private parts from an onlooker [as defined in the footnote pertaining to Ruling 784] or he cannot remove the usurped clothing, he must continue the prayer with that clothing and the prayer will be valid.