Must one make up or offer expiation for masturbating out of ignorance of its prohibition while fasting an obligatory fast? And does masturbation invalidate the fast, and what is the ruling on one who ejaculates while fasting merely by seeing or thinking of something that incites lust?

The majority of scholars hold the view that masturbation invalidates fasting, and this is the preferred and authoritative opinion. Some Hanafis, Al-Albani, and Ibn Hazm differed on this matter.

The fast of someone ignorant of the prohibition of masturbation or of it invalidating the fast is valid. However, for someone who knows the prohibition of masturbation but is ignorant of it invalidating the fast, their fast is invalid if ejaculation occurs.

Ejaculation due to thinking does not invalidate the fast according to the majority of scholars. As for ejaculation due to looking, it has multiple scenarios.