a high note is a recording you take when you are high. something you say when your high that's funny as hell and you gotta listen to it the next day. High notes can range from just a simple phrase, to an impression, or an ill ass freestyle.
One night me and my friend were stoned off our asses while we were driving in my car and we decided to record what we were saying on our phones. ive had them recorded on their ever since and anytime i need a laugh, thats where i go.