I have use the car/ highway analogy. Here's how I do it: I imagine that I'm standing on one of those remote highway overpasses- nothing much around, but I can look down at the cars. I don't try to focus in on details, just let whatever come. Temperature? The feel of sun or rain? Sound of the cars? Smell? Just whatever. Think of it as more observing and less analyzing.

Another favorite is imagining a big old monster- like one from a children's book, so not very threatening. You invite it to sit next to you and acknowledge it's there, but you don't give it attention or feed it. You just accept it's presence.

My all time go-to is to imagine that I'm floating in an inner tube down a gentle river. Just ride it out and enjoy the floating sensation as best you can.

In earlier days of doing things like this, I found it helpful to say to myself "what if or what is?" To distinguish whether something was a what if in my head or something that really was.

It's interesting you mention being on or off with the emotions. I have never thought much about it, but my anxiety can drag and then just suddenly seem "off" or gone. Maybe that's not unusual, given how intense the experience can feel?

Hope you are doing okay today.