From Mujahid (may Allah be pleased with him) who said: Whenever a man has sex with a woman of his household, and does not invoke Allah [i.e. say Bismillah...], the genies [jann] wrap themselves around his shaft and perform the sex with him.
- Al-Hakim Al-Tirmidhi, Nawadir Al-usul fi Ahadith Al-Rusul [Anecdotes of the Foundations of the Hadith of the Messenger], The seventy-sixth foundation

Mujahid said: Whenever a man has sex, and does not say "Bismillah...", the genies wrap themselves around his shaft and perform the sex with him; this is the word of the Most High: { No man or jinn before them has caused them to bleed from sex }