Mishkat al-Masabih 13 Marriage كتاب النكاح 112

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِنَّ الَّذِي يَأْتِي امْرَأَتَهُ فِي دُبُرِهَا لَا يَنْظُرُ اللَّهُ إِلَيْهِ» . رَوَاهُ فِي شرح السّنة

He reported God’s Messenger as saying, “God will not look at him who has intercourse with his wife through her anus.” It is transmitted in Sharh as-sunna .