I asked the Messenger of Allah ﷺ about a man who has intercourse with a woman but does not ejaculate. He replied, "He should wash whatever of the woman's fluid touched him, then perform ablution and pray."
سألت رسول الله ﷺ عن الرجل يصيب من المرأة ثم يكسل؟ فقال: يغسل ما أصابه من المرأة، ثم يتوضأ ويصلي.
Bukhari narrated it in the Book of Ghusl (293) and Muslim narrated it in the Book of Menstruation (346), and the wording given here is Muslim's. Both of them narrated it through Hisham bin Urwa, from his father, from Abu Ayub, from Ubayy bin Kaab, who related the hadith. In one wording, it reads, "If a man has intercourse with a woman but does not ejaculate, what should he do?" He said, "He should wash whatever of him touched the woman, then perform wudu and pray." This is how it appears in Bukhari's wording. Abu Abdullah (Bukhari) said, "Ghusl is more cautious, and that other view exists as well, we have simply explained their disagreement." As the Hafiz explained, the meaning is that if it cannot be established which hadith abrogates the other, and no preference becomes clear, then caution regarding one's religion calls for performing ghusl. End of quote.This means that Bukhari does not hold ghusl to be obligatory except through ejaculation. This is supported by what he narrated from the hadith of Abu Hurairah, "If he sits between her four limbs and then exerts himself with her, ghusl becomes obligatory" (number 291), where the intended meaning of "exertion" is ejaculation. Bukhari's purpose was to clarify the disagreement among the companions and the successors, showing that in the early period of Islam the practice was based on the hadith of Uthman and Ubayy bin Kaab, and that ghusl was more cautious, meaning it was recommended. Since the later abrogating hadith of Ubayy bin Kaab was not firmly established in his view, due to disagreement over Zuhri's transmission, he did not include it.