Place you hand or fist on your partner and feel him breathe. Avoid pressing on him in any way and simply touch. Allow your breathing to sync and at any point sink you fist into your partner as you feel an opening or sifting. In this sinking simply move your body and relax the arm so it screws inward along with the opening in your partner density and allow your breath to keep going without stop. Do this several times for each arm and than move on to this:

Breath with your partner as you contact him without support and at some point change your breathing and see how this affects your partner. Do this several times and than progress to sinking in your partner as you change your breath and also a little before and a little after. The same can be done walking together and changing breathing pattern at once and noticing the difference and than adding a change in direction.

This is a sutle drill but the benefits to your striking will be very noticeable.

Have fun and change and vary each time you work. Learning and cleaning are the goals not the drill itself.