Dvadasi (the day after ekadasi):
Parana (Breaking the fast):
One should break the fast after the sunrise of the dvadasi, after the first quarter of the dvadasi tithi has passed, but before the dvadasi tithi has ended. (timings are there on our calendar)
After taking morning bath, one should offer the upavasa to the Lord:
ajnana timirandhasya vratenanena kesava
prasida sumukho natha jnana drsti bhava
Oh Kesava, be pleased with this vrata performed by one fallen in the modes of darkness. Oh Lord, bestow your glance of knowledge upon me.
One should observe similar rules as on dasami. For health and common sense, what to speak of spiritual development, it is wise to eat only once going into a fast and coming out of a fast. The meal should also be light.
From an Ayurvedic perspective, especially if one is fasting entirely, or even just taking water, the malas (stools) absorb the toxins in the body when fasting. So on the day the fast is broken it is a good idea to take a gentle laxative consisting of 50-50 warm milk and water, with some rock candy to sweeten it. Generally 4-5 cups are drunk (up to 7) and within half an hour to an hour one will expell the malas. After this at lunch time one takes one's meal of prasadam.
One should not bathe the deity on the dvadasi day, but bathe the Lord in ghee in the night. But if one does, then it should be performed before sunrise.
Sometimes, due to the manner in which the ekadasi tithi and the dvadasi tithis are positioned in relation to the sunrise (there are six different cases), the vrata is observed on the dvadasi and the fast is broken the next day, the trayodasi. Such a fast day is called a mahadvadasi, to distinguish it from a regular dvadasi, which is the day to break the ekadasi fast.