Not all your mirroring has to use the same parts of the body, just as your symbolic mirroring does not necessarily use exactly the same words. For example, NLP teaches that you can make a motion such as finger taps that match the rhythm of the breath, rather than breathing to the breath timing yourself. This is called an exchanged match. You are exchanging body parts, but matching the rhythm or other mirroring aspect.
If you are a man and you’re matching a woman in front of you, avoid looking at her breasts, trying to figure out her breathing pattern! You will get caught, and using the excuse, “I was trying to match your breathing.” will not work in this case. Look at her shoulders instead; those tiny movements up and down will give you a hint on the breathing pattern she is using, and by applying exchanged matching you can move your leg or hand up and down accordingly.
You will be surprised to find out that in such a case of exchanged matching a breathing pattern, if you increase the speed of your matched movement, their breathing becomes faster! And if you slow it down, their breathing also becomes deeper and slower.