The sound when Link from the Zelda series swings his sword.
It's often in a line of yells which are screamed by Adult Link in The Ocarina of Time. See hid and sjaad as well
Either liquid niquil or any liquid drink with melatonin, Ashwaganda or other sleeping aids in a liquid form. If warm tea helps you get to sleep that could be sleepy juice too.
I could not sleep so I chugged some sleepy juice and now I'm so tired and sleepy.