Abu Hurairah (RA) reported: The Apostle of Allah (ﷺ) said: When a man has sexual intercourse, bathing becomes obligatory (both for the male and the female). In the hadith of Matar the words are: Even if there is no orgasm. Zuhair has narrated it with a minor alteration of words.
Shu’bah narrated from Qatadah with the remaining chain of transmission. The difference is that in Shu’bah’s narration, instead of "then «جهدها»", it is "«ثم اجتهد»" (then performed sa’i), and the words "«وإن لم ينزل»" (even if there is no ejaculation) are not present.
With two different chains of narration, it is reported from Abu Burdah, from (his father) Hazrat Abu Musa (may Allah be pleased with him), that in this matter a group of the Muhajirun and Ansar differed. The Ansar said: Ghusl (ritual bath) becomes obligatory only when (semen) is ejaculated forcefully or water (i.e., ejaculation) occurs. The Muhajirun said: Rather, ghusl becomes obligatory when there is intercourse. (Abu Burdah) said: Hazrat Abu Musa (may Allah be pleased with him) said: I will resolve this issue for you. I got up and sought permission to visit Hazrat Aisha (may Allah be pleased with her). When I was granted permission, I said: My mother, or he said: O Mother of the Believers! I want to ask you about something, and I also feel shy before you. She said: Do not be shy to ask me about anything you could have asked your own mother who gave birth to you, for I am also your mother. I said: So what act makes ghusl obligatory? She said: You have come to the one who is best informed about this matter. The Messenger of Allah (peace and blessings be upon him) said: "When he (the man) sits between her (the woman’s) four limbs and the circumcised parts touch each other, then ghusl becomes obligatory."
'A'isha the wife of the Apostle of Allah (ﷺ) reported. A person asked the Messenger of Allah (ﷺ) about one who has sexual intercourse with his wife and parts away (without orgasm) whether bathing is obligatory for him. 'A'isha was sitting by him. The Messenger of Allah (ﷺ) said: I and she (the Mother of the Faithful) do it and then take a bath.