نبي الله ﷺ قال إذا جلس بين شُعبها الأربع ثم جهدها فقد وجب عليه الغسل
صحيح مسلم
The Prophet of Allah (SAW) said: “Whenever a man sits between a woman’s four limbs and goes at it hard with her, it is obligatory for him to wash.”
Sahih Muslim