The king of scholars, Al-Kasani, said in Badā'i' al-Ṣanā'i' 2: 90: "Fasting is invalidated when its essential element is missed, which is: eating, drinking, and sexual intercourse, whether in form and meaning, or in form without meaning, or in meaning without form, and whether it is done without excuse or with an excuse, and whether it is done intentionally or by mistake, willingly or unwillingly, after having been mindful of his fast, not forgetting or in the sense of forgetting." By his saying 'form and meaning,' he means the usual eating and drinking, and the usual sexual intercourse. He means by the form of eating and drinking and their meaning: delivering what is intended for nourishment or healing to his stomach from the mouth; because through this, the desire of the belly is fulfilled completely. And he means by the form of sexual intercourse and its meaning: the penetration of the male organ into the female organ; because the complete fulfillment of the desire of the private parts cannot be achieved except through it.