Sayyiduna Abu Hurairah (may Allah be pleased with him) reports that the Noble Prophet (peace and blessings be upon him) said: When a man sits between the four parts of a woman and exerts himself for intercourse with her, then ghusl (ritual bath) becomes obligatory.
Hadith Referenceاللؤلؤ والمرجان / كتاب الحيض / 199
Hadith Gradingمحدثین:«صحیح»
Hadith Takhrij«صحیح، أخرجه البخاري في: 5 كتاب الغسل: 28 باب إذا التقى الختانان»