Dua What To Say Before Marital Relations

"If any one of you, before having sexual intercourse with his wife, says:
بِسْمِ اللَّهِ اللَّهمَّ جَنِّبْنَا الشَّيْطَانَ، وَجَنِّبِ الشَّيْطَانَ مَا رَزَقْتَنَا
'Bismillah. Allahumma jannibnash shaitaana, wa jannibish shaitaana ma razaqtana.'
(In the Name of Allah. O Allah, protect me from Satan, and protect what you bestow on us [i.e. offspring] from Satan.)
And if it is destined that they should have a child, then Satan will never be able to harm that child." (B & M)