What does allnighter high mean?

allnighter high meaning in Urban Dictionary

That period between about 6am and noon whenever, after staying up through the night, you are both strangely stimulated and pleased, as if drunk and high at precisely the same time. This will be used swiftly and instantly with an allnighter crash, which often becomes an allnighter hangover... but for enough time becoming, you have attained a state of serenity that you'll seldom feel once more... at the very least until your following term paper.