Sunan Ibn Majah, Book 9, Hadith 1999 (In-Book) ⓘ
It was narrated from Khuzaimah bin Thabit: That the Messenger of Allah said: “Allah is not too shy to tell the truth,” three times. “Do not have intercourse with women in their buttocks.”
حَدَّثَنَا أَحْمَدُ بْنُ عَبْدَةَ، أَنْبَأَنَا عَبْدُ الْوَاحِدِ بْنُ زِيَادٍ، عَنْ حَجَّاجِ بْنِ أَرْطَاةَ، عَنْ عَمْرِو بْنِ شُعَيْبٍ، عَنْ عَبْدِ اللَّهِ بْنِ هَرَمِيٍّ، عَنْ خُزَيْمَةَ بْنِ ثَابِتٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " إِنَّ اللَّهَ لاَ يَسْتَحْيِي مِنَ الْحَقِّ " . ثَلاَثَ مَرَّاتٍ لاَ تَأْتُوا النِّسَاءَ فِي أَدْبَارِهِنَّ " .
also referenced under: Hadith 1924 (Reference) & Volume 3, Book 9, Hadith 1924 (DarusSalam)