If we awaken after chatzos, halachic midnight, with the intention of staying up for a while, for example, sitting and learning, and then going back to sleep, the halachah is to recite the prayer of Elokai Neshamah without the conclusion of “Baruch Ata Hashem hamachazir neshamos lifgarim meisim.” However, if we stay up for just a couple of minutes, poskim agree that we do not have to say Elokai Neshamah. The second time we wake up, we should say the full prayer of Elokai Neshamah. We wash negel vaser every time we awaken, day or night, but the brachah “Al netilas yadayim” is said only once, the first time we wake up for the day, even if it is still night. There are, however, many poskim who say that we are not required to say al netilas yadayim the first time, even if we stay awake for a while, and then go back to sleep until the morning; we may say it the first time we awaken, or choose to say it the second time together with the other morning brachos, and closer to the time for davening Shacharis.