Bulugh al-Maram, Book 1, Hadith 116 (English) ⓘ
Narrated Abu Huraira (rad): Allah’s Messenger said that, “If one of you sits between her legs (of a woman) and penetrates her, Ghusl (bath) is obligatory.” [Agreed upon].
وَعَنْ أَبِي هُرَيْرَةَ - رضى الله عنه - قَالَ: قَالَ رَسُولُ اَللَّهِ - صلى الله عليه وسلم -{ إِذَا جَلَسَ بَيْنَ شُعَبِهَا اَلْأَرْبَعِ, ثُمَّ جَهَدَهَا, فَقَدْ وَجَبَ اَلْغُسْلُ } مُتَّفَقٌ عَلَيْه ِ (130). 3 - صحيح. رواه البخاري (291)، ومسلم (348).
also referenced under: Book 1, Hadith 130 (In-Book)