Imagery is most typically used in a visual format. Your personal trainer or dance teacher demonstrates a movement, you watch and then try to copy it. But imagery can include so many more options than just visual! You're familiar with auditory imagery, in the form of someone telling you, not demonstrating, what to do. You listen to the instructions and you try to execute them. But how about using non-traditional auditory imagery... like a sound. Not words and language-sounds, but the sound of a sigh.
Sigh out loud. Right now. Like a cartoon sigh. Or like the appreciative sigh of getting a massage. Or like the satisfied sigh of appreciating the sunset from a location you love.
Do it again. How does a sigh feel? Never thought about it? That's ok, think about it now. Sigh again and sense the sigh with ALL of your senses. Your hearing, your skin, what does someone look like when they sigh in satisfaction and release. Think about it for a moment and enjoy it as much as your dog does when he yawns.
Now touch your right shoulder, tap it with the fingertips of your left hand. Lift your right shoulder up to your ear and as you lower it, perform your sigh. Theatrically, yes, but with an open query: can my shoulder sigh? I promise you, it can. Embody the sighing shoulder about 6x. Afterward, notice how your shoulders feel. Compare the right shoulder to the left. Does it feel different? How? Do you like it? Yeah, I know. Feels pretty good, doesn't it? Repeat this on your other shoulder.
Once you have done this little exercise about 8 or 10 times, over the span of 2 weeks or so, you will start to have a feeling for sighing shoulders. At that point, when you're at your computer and you realize your shoulders and neck are tense, you'll be able to do something about it immediately. You should have enough experience by then that you can mentally sigh your shoulders down and into relaxation. Take a breath in, exhale and hear the deep and satisfied sigh in your imagination as you feel your shoulder muscles relaxing. By then, you won't need to make a sound; you will have the experience embedded in your nervous system and you'll be able to generate it at will.
P.S. I found this image of feet yawning. Now *there's* a visual image to go with your new auditory image!