One of the techniques that Shinzen Young teaches is to move into the tension in order to relax.
So, if you’re sitting in stillness, meditating, rather than ‘trying to relax’, he asks you to tense and tighten every muscle in your body as firmly as you can … and then after a few seconds, to release the tension.
How simple and brilliant this is.
Try it for yourself, and you’ll see.
Perhaps it’s true that you must allow yourself to fully feel the extent of an undesirable feeling, in order to experience is desired complement.