Moreover, it must be an original organ, as a precaution concerning an intersex person, since the penis of an intersex person is not necessarily original: if it becomes clear that the person is female, then it is an extra appendage; and if the matter remains ambiguous, ablution is not invalidated in the presence of such uncertainty.
His statement, “or a woman’s private part”: the private part refers to that of a woman. It is stipulated that it be original, thereby excluding the private part of an intersex person.
His statement, “with the back or palm of his hand,” is connected to “touching”; that is, the touch must be with the hand, whether with its edge, palm, or back.
The author specifically mentioned the back of the hand because some scholars hold that touching with the back of the hand does not invalidate ablution (1), since touching and grasping are ordinarily done only with the palm of the hand . . .
Touching with anything other than the hand does not invalidate ablution, because the hadiths concerning touching specify the hand, such as his ﷺ statement: “Whoever makes direct contact with his penis by his hand, with no barrier between them, ablution has become obligatory upon him” (2). When used without qualification, “hand” refers only to the palm, as Allah Most High says: “As for the thief, male or female, cut off their hands” [al-Ma'idah 5:38]—that is, their hands at the wrists.
The scholars differed regarding the touching of the penis and a woman’s private part: does it invalidate ablution or not? There are several views: