Is the fast invalidated and is expiation due if sexual intercourse occurs while a man is asleep with an erection?
General Chapter
Al-Mughni
Book of Fasting
Primary text
If a man's penis is erect during sleep and his wife engages in intercourse with him, neither making up the fast (Qada') nor expiation is due according to Ibn Aqil. This is the position held by Al-Shafi'i. The rationale is that the act nullifying the fast occurred without his choice, similar to a fly being blown into the throat by the wind; therefore, the fast is not broken.
Supporting text
The apparent statement of Ahmad suggests that making up the fast (Qada') is obligatory. This is derived from his ruling that a woman who is forcibly raped must make up her fast, meaning the man's situation is analogous or more strictly held. Furthermore, sexual intercourse invalidates the fast just as it invalidates Hajj, and its severity is underscored by the requirement of expiation and the imposition of the *hadd* punishment if it constituted Zina (adultery/fornication), distinguishing it from other prohibitions in Hajj.