When you don't know what or how to note you can always note, "Don't Know", "Uncertain", "Pass", "Thank You", or any variation on that theme.
The Safety Release Valve Note is a mechanism, created by Kenneth Folk, by which one always has a way to pass, if they aren't sure what to say. The way it works is when you don't know what to say you can always note, "Don't Know", "Uncertain", "Pass", "Thank You" (particularly good for Social Metta practices) or any variation on that theme.
The Safety Release Valve was originally designed for Social Noting practices, to help reduce social anxiety that can build up around not being sure what to note (especially for beginners) and to keep the flow of the noting practice unimpeded by excessive deliberation. It can be used with any practice listed on this guide, unless the notes on that practice recommend otherwise (ex. Binary Noting & Just Noting).