Is it permissible for a husband to fondle his wife between the buttocks without penetration into the anus, with external touching of the anus? Is this permissible during menstruation? Is ghusl (ritual bath) obligatory upon the wife in this case? Should ghusl from janabah (ritual impurity requiring a full bath) be performed during menstruation or after its completion?

The forbidden act is the insertion of the male organ into the anus. Foreplay between the buttocks is permissible, even during menstruation, provided it does not lead to forbidden penetration into the anus or vagina during menstruation, as the Prophet, peace be upon him, forbade approaching women through their anuses. It is advisable to avoid this and utilize the lawful place of cultivation, based on the Almighty's saying: "Your wives are a place of cultivation for you, so come to your place of cultivation however you wish."

Regarding ghusl (ritual bath): - In the case of foreplay without penetration, ghusl is not required unless ejaculation occurs. - In the case of foreplay with penetration into the anus, ghusl is obligatory for both spouses, and this penetration is unlawful and a major sin. - If a menstruating woman becomes junub (in a state of ritual impurity requiring ghusl), she is not required to perform ghusl until she becomes clean from menstruation. Then, she performs one ghusl for both janabah and menstruation together, as mentioned by Al-Shafi'i and Ibn Qudamah.