You can do the 3-2-1 Process anytime you need it. Two particularly useful times are right when you wake up in the morning and just before going to bed at night. Once you know 3-2-1, it only takes a minute to use it for anything that might be disturbing you.
First thing in the morning (before getting out of bed) review your dreams and find someone who showed up with an emotional charge, positive or negative. FACE that person, holding them in mind. Then TALK to that person, or simply resonate with them. Finally, BE that person by taking their perspective. For the sake of this exercise, there is no need to write anything out—you can go through the whole process right in your own mind.
Before going to bed, choose a person who either disturbed or attracted you during the day. FACE them, TALK to them, and then BE them (as described above).
Again, you can do the 3-2-1 process quietly by yourself, any time you need it, day or night.