To be incredibly exhausted and tired, to the point of deliriousness. Often implies the exhibition of strange behaviours (weird verbalisations and lack of coordination) due to exhaustion.
Originated from a mispronounciation of drowsy (possibly due to exhaustion): dwousy.... Dwizzy
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.