839. Shulchan Orech
119:8 Next, the meal is eaten. A person should eat the entire meal while leaning. There is a practice to eat eggs. A wise person will have the foresight not to fill up his stomach so that he can eat the afikomen according to its mitzvah and not in an unseemly manner. We do not eat roasted meat on the Seder nights, not even of chicken (which could not have been used as the Pesach offering), not even if it was boiled before roasting. The practice is not to dip foods on Pesach night other than those used for the Seder so that it will be obvious that we are doing so in order to fulfill the mitzvah.
After finishing the meal, the afikomen is eaten as a reminder of the Pesach offering, which was eaten at the end of the meal. One should eat two olive-size portions of afikomen, one as a reminder of the Pesach offering and one as a reminder of the matzah that was eaten together with it. In any case, one should not eat less than a single k'zayis. One eats the afikomen while leaning, after which it is forbidden to eat anything. (If one neglects to lean while eating the afikomen, he need not do it again if doing so would be too difficult for him - Mishnah Brurah 477:4. If one ate after the afikomen, he must eat anither k'zayis of matzah - MB 478:1.) One then pours the third cup of wine, which will be used for bentching. One must check carefully that there aren't any dregs of wine into which matzah crumbs might have fallen during the meal. If the cup is not clean, it must be washed and rinsed. It is preferable to bentch with a zimmun of three but one should not go from house to house to assemble a zimmun because everyone needs to bentch where they ate. It is customary that the head of the household leads bentching as per Proverbs 22:9, "The one who has a generous eye will be blessed" and an example of a "good eye" (ayin tov) is that the Seder leader says, "Whoever is hungry, let him come and eat." We bentch over the cup of wine, which we drink while leaning. It is forbidden to drink in between the third and fourth cups.
119:9 After bentching, the fourth cup is poured. The practice is to open the door as a reminder that this night is protected; we are not afraid of anything and, because of our faith, Moshiach will come and G-d will pour out His anger on idolators. We therefore say "Pour out Your wrath...." Then we continue the Haggadah beginning from Lo Lanu ("Not to us..."). When we reach Hodu ("praise G-d"), if there are three present - even if the three include his wife and his minor son who has reached the age of education - he says Hodu and the others respond as we do in shul (though it is preferable to have three adult males present for this - MB 479:9). One must drink a whole revi'is (about 3.3 ounces) from the fourth cup, after which he recites the concluding bracha and finishes the Haggadah. One may not drink anything after the four cups of wine except for water. If one is not tired after finishing the Haggadah, he should recite Shir HaShirim (or discuss the laws of Pesach, the miracles, etc. - OC 481:2). It is customary not to recite the normal bedtime prayers other than the first paragraph of Shema and the bracha HaMapil. This is to demonstrate that it is a night on which we are guarded from harm and there is no need for additional protection.